Check out
www.turbotax.com. They've been the only online filing service that has ever handled all facets of filing for myself, being an overseas filer. Just to be aware, the federal and state taxes will have to be filed by post because they don't yet accept electronic filing for those living outside the US.
You can also contact a live person, if need be (for a fee), which might be useful for back-filing for 2002 and 2003.
In your situation, you will include the W-2 information for the part of 2002 you worked and then you will also exclude the income from December 2, 2002-December 31, 2002 (basically one month's pay) as it will most likely be under the $80,000 threshold. Remember, the US tax year runs over the calendar year (unlike the UK) so it only takes into account income from January 1-December 31. I know when I moved over halfway through the year, I got a really good refund. For 2003, you most likely will have a $0 liability so at least you shouldn't be penalized for owing tax money!
Hope this helps,
Matt