£90 per year (premium version) is rather a lot of money to insure 1 gadget, but there again if you are clumsy, careless, or forgetful, it could well be worth the peace of mind. 🙂
If you were to do some damage in the first two years then yes, it's worth it. Anytime after that it isn't because you've basically paid insurance for two years and I think that comes close enough to the price of the new phone.
In other words, if you screw it up the first year it would be a great deal because it would have cost you less than the price of the new phone should you need to replace it yourself.
You can probably take out a policy with your homeowners insurance and it'll be way cheaper than that. My $2300 Macbook Pro only costs me $50/year to insure
Will there be insurance for the iPhone 3G over the pond on AT&T? Seeing as it is being treated more like every other phone/smart phone it should, but you never know. Has it been announced whether or not insurance will be available yet?