While Intel is looking to push DDR3 beginning this year, AMD will be sticking with DDR2 for the launch of their new quad-core line. On top of that, their quad-core chips will support DDR2-1066 memory, which is currently the fastest stock that support is seen for. The idea is for future JEDEC standards to be compatible with the memory controller on AMD's CPUs, making supporting or adding support for newer memory a simple task. I look forward to seeing how the new multi-core design AMD has in store for us will work with RAM this fast, and how it will compare to Intel's designs.
Their DDR3-supporting processors aren't expected into 2008, but as time marches on it appears that Intel may be in that same boat.