http://news.bbc.co.uk/1/hi/technology/4715612.stm
Potential issues:
1) The evidence against him hasn't been under the scrutiny of a British court
2) We are perfectly capable of trying such an offence in this country
3) The sentence (up to 70 years) is vastly disproportionate to the crime - he wouldn't get that much for murder over here.
4) Our so-called extradition treaty with the US only applies to one-way traffic (and it's not in our direction) and I believe hasn't actually been made law yet.
5) He will be tried in Virginia and accused of being a terrorist - is he likely to get an impartial jury?
So yeah, I think he should be tried here. Would be interested to hear from those with alternative views.
There's also the rather crazy aspects of his story - the fact he could waltz in without passwords, using a
dialup modem. I mean, not only is it slightly crazy to run Windows in security-sensitive situations, but the US Navy for example actually runs beta-versions of Microsoft software

Time for a change in IT policy? A google for "Windows for warships" will turn up a similar controversy on this side of the Pond.