GVXMPP is a very new application that delivers your Google Voice SMS messages over XMPP (Jabber). There are other solutions out there, but ours does not require your Google username or password.
There is an android app on the market which needs some testers (of both the app and the GVXMPP system in general). Head on over to http://www.gvxmpp.com/ and create an account, then download the app from the market.
Feedback (good or bad) is greatly appreciated.
http://www.gvxmpp.com/signup - Account Creation
http://www.gvxmpp.com/download - QR Barcode Link