We are Planning to use Seam 2.1.2.
Is there any Compatibilty Issues With Seam 2.1.2 and Richfaces 3.3.3 and Jboss 4.2.3 and Java 1.6?
There are no known compatibility issues there. That is a very common configuration. If you do find issues with integration here please let us know.
The best place is here for Seam, and the RichFaces user forum if it is RichFaces related.