I must have not been looking. A new version of Netstumbler came out late last month. The 0.4 release sports a help file and compatability with more cards. There is also a new release of Ministumbler (for Pocket PC) out. Thanks to a series of semi-dark tips on yesterdays The Screen Savers (which makes great background at 8am) for the heads up.
On *nixen, Kismet is the wiffy sniffer of choice. Kismac is supposed to be a really pretty but functional GUI interface for OSX.