On some other topic i found that seam also provides some rest support. If you have to choose a framework to develop restul services, which will you choose: seam or jersey? And what are the differences etween those two (besides the fact that seam has also many other features)?
Seam doesn't have any REST (not official JSR 311 support) on it's own. You need to use RESTeasy for that (though you should be able to use any other JSR 311 implementation), so it really becomes a Jersey vs RESTeasy question, at least AFAIK.
Yeah, RESTEasy actually integrate pretty deep into Seam. For instance, you can get Seam context objects as RESTful resources. That goes way beyond those simple stateless RESTful services.