FUD Zilla says it may take AMD another month to sample their first AM3 chips:
Deneb has a combo memory controller so every chip should support DDR2 and DDR3 but at this early stage, we understand that we will see different versions of the chip - one supporting AM2 and another AM3. Its a bit fuzzy how AMD plans to do that but we know you will need the latest 790GX and 790FX+SB750 boards to make them running.
The production and sales of DDR3 Deneb will start in Q1 2009 initially at some modest speeds and at some higher speeds later, and with Nehalem's DDR3 market boost AMD will jump at the right time to get some optimal pricing for the DDR3 memory.
The site also writes Propus, a L3 cacheless version of Deneb, may arrive in late Q1 2009 or Q2 2009.