Geneva now supports SharePoint 2007

Geneva Team released beta 2 of the server and the framework. In the list of new features is supporting SharePoint 2007. This means that SharePoint 2007 could potentially connect to a STS server and be a Claim Based application.

http://blogs.msdn.com/card/archive/2009/05/12/what-s-new-in-geneva-beta-2.aspx

SP2 for MOSS was released a while ago, and in the enhancements was a better integration between client applications and FBA for SharePoint.