There is a 2007 update to this post containing more recent information.

Over the years, I've bought numerous items from online mail order computer/electronics stores, and almost every time have been surprised by the high surcharge on deliveries to Northern Ireland (which can also render price comparison sites all but useless). Obviously as an outlying area extra costs may be incurred posting here but some of the charges are ridiculous. For example, I recently noticed one site, Novatech.com, where I spotted an item I'd been searching for for £4.50 and thought fantastic! Of course when it came time to checkout I was advised that I would pay nearly £16.50 to have that one little box delivered to Belfast. That's ok if you're spending a few hundred pounds, but when your delivery surcharge is more than the cost of the item(s), it's absurd.

There are ways round this of course. Some companies have reasonable postage policies for Northern Ireland, many charging the same rate as any other region of the UK - including every seller I've ever come across on ebay. Unfortunately, ebay isn't always an option, so for the benefit of any techies like me out there, I decided to do a little bit of investigative blogging and here's the rundown. I priced a wireless network card (Netgear's WG311 - between £21-£28) and proceeded to the checkout to investigate the postage costs. What I found at some online shops disturbed me.

Note: Since writing this, delivery prices have changed somewhat. Scan are now a rip-off at somewhere between ££15 and £25, while Dabs have reduced their NI surcharge to a more reasonable ££4.

The Good
Amazon - Although their individual item prices are some of the most expensive, including their price for the Netgear WG311 card, their free "Super-Saver" delivery on items over £15 means that Amazon are fairly decent if you're only ordering one item.
Total: £23.53 for the card + £0 postage = £23.53

Overclock.co.uk - I don't think I've ever placed an order from Overclock.co.uk, but they have a nice site and seem quite competitive. Overall they originally had the best price for the network card I was looking for, however Amazon's price reduction meant Amazon pipped them to the top spot.
Total: £22.05 for the card + £2.94 postage = £24.99

Dabs - These are the guys who used to charge less for delivery to the Republic than they did to Northern Ireland (or the Channel Islands, Isle of Man or far north Scotland). Actually I think they still do, but it's similar at least. I used to order a lot from them when their surcharge was a fiver because their prices for the items themselves are quite good and their service was reasonable too. When they upped it to £11.75 though, that obviously put me off and I think I've only ordered once (if that) since they reduced it again because I forget to even think of them.
Total: £25.85 for the card + £8.99 postage = £34.84*

Komplett - I've used Komplett just the once, for my MP3 player if I recall correctly, however they have the same delivery policy as Scan, treating Northern Ireland deliveries the same as any other UK deliveries. Like Scan, they didn't have the exact same card, so I used the same average price.
Total: £25.00 for the card + £6.75 postage = £31.75

Follow up:

The Good-ish

Overclockers UK - They're not bad, but I couldn't put them in the good category because when I originally investiaged they charged a whopping £17.57 for Northern Ireland (next day Citylink) delivery. However their charge isn't a surcharge, it's instead (ie not on top of) the standard UK rate of £9.46). I've ordered from them before, but only when I was ordering more than one item and/or something that could be posted through Royal Mail.
When the price of the WG311 came down below £25 (I presume that's the reason, before it was £28.14) Royal Mail special delivery is available at £9.46
Total: £23.95 for the card + £17.57 postage = £45.71

The Bad

Scan.co.uk - I've used Scan multiple times over the years and have always found them fantastic to buy from, a really great retailer. They even send you a text message to your mobile to let you know when your order is dispatched (last time I placed an order it was sent within 3-4 hours).
Well, that was when they didn't charge any extra for delivery to Northern Ireland on top of their standard UK delivery (£7). That has since changed and on my last check they wanted £15.82 + VAT (about £18.50). They don't stock the particular make of card I was looking for, so I'm allowing for an average price of £25.00
Total: £25.00 for the card + £18.50 postage = £43.50 *

Savastore - "If you live in Northern Ireland delivery is an additional £15 to the variable delivery rate chargeable for your items." Exactly what everyone wants to hear. Savastore's price hasn't come down since I originally researched this, remaining at £26.44 from mid-August. However I think delivery has gone up!! What makes it even worse is they don’t display the surcharge at checkout, making it even harder to work out what you're paying (or maybe I could have got away without paying the surcharge?)
Total: £26.44 for the card + £17.03 postage = £40.26

Misco - Misco's price for this item has also remained constant at £27.01. Their special rate for delivery to Northern Ireland is £17.63 - ouch!
Total: £27.01 for the card + £17.63 postage = £44.64

Novatech - Novatech's site currently features a big banner at the top advertising "Next Day Delivery from Only £4.49." Apparently not if you're having it delivered to Northern Ireland though. Their NI delivery charge of 17.03 made their good starting price of £23.23 jump to a not-so-reasonable £40.26!
Total: £23.23 for the card + £17.03 postage = £40.26

The Ugly

Ebuyer.com - Ebuyer generally have very good prices on their goods but an absolutely whopping surcharge of £17.63 for Northern Ireland delivery. As a surcharge, this is on top of their standard UK delivery charge making them one of the worst offenders. The delivery was only pennies away from being more than the card itself!
Total: £21.50 for the card + £3.22 standard postage + £17.63 NI postage = £47.10

What to do?

The only conclusion I can draw from this is that if you're ordering something small and cheap, avoid Savastore, eBuyer etc. The delivery charges make an enormous difference - with the prices of this card ranging from £23.53 to over £47 - more than double the price! Check the prices of Dabs, Amazon and the two overclocking stores: Overclock.co.uk and Overclockers.co.uk.

With bigger orders, Dabs are still worth a look, Amazon and Overclock.co.uk, but it might also be worth checking out eBuyer, Savastore and Misco. Those £15-£20 surcharges aren't so bad when you're buying £500 pounds worth of goods anyway.

* Price adjusted based to account for updated delivery charges