i have the same problem in many public wi-fi networks;(
I'm having some issues connecting my new HTC Touch Diamond smartphone to wifi stations in airports, although have no problems with it at home (http://www.mypocketpcmobile.com/FullReviewHTCTouchDiamond/tabid/247/Default.aspx)
I bought it primarily to use for business travel, so this is a bit of an issue for me! Plus my network provider (T Mobile UK) is being very unhelpful.
Any ideas would be welcome.