Lydia Ash, a tester I used to work with on Outlook Web Access (and have a huge amount of respect for), has written a book about testing for the web: The Web Testing Companion, coming out in May 2003. She got a great review on StickyMinds as well. Way to go, Lydia!
I'd really like to write a book this year but I don't think i'll have any time.
No doubt i'll be working on some projects for MS PAG so maybe MS Press will convert some of them ;)