I see there is only the 8800 that has a 4.2 available.
Does anyone know what's new?

I guess we can expect 4.2 for other device next year (they are so slooooow ).

4.2 has been out on the 8100 Pearl since last September. Check out the 8100 and 8800 forums for lots of info on what's new in 4.2. The 8800 actually has 4.2.1 while the Pearl is still running on 4.2.0