I have a Netgear DG 834 which works well. The latest models are faster in terms of streaming video etc, if you need that facility. Do make sure you consider the security implications of having a wireless set-up. There is a thread here:
http://www.pprune.org/forums/showthread.php?t=296624 I don't personally know of any Vista compatibilities, but if you set it up from the XP machine, via a hardwired LAN connection you should always be able to access it via your web browser and make any alterations necessary.