You can find many of Microsoft's codenames here:

http://en.wikipedia.org/wiki/List_of_Microsoft_codenames#Win...

My favourite codename sniping had to do with Windows NT (codename Cairo) and NeXT. When announcing NeXTSTEP 4.0 (codename Mecca), Jobs quipped, "Why stop at Cairo when you can go all the way to Mecca?"

http://www.paullynch.org/NeXTSTEP/Expo.1994.htmld/