If you are wondering what benefit DDR3 would bring, I suggest reading up an article over at LostCircuits. I suggest you guys review this link, though it's been quite dated already (and focusing on GDDR3). Expand for more...
i just got info from supertalent that DDR3 motherboard will start shipping in mid 2007, that DDR3 wont be pin compatible with DDR2.
Also they already have finished prototypes of DDR3 they are testing the in several mobos now.
All this info will be public tomorrow when ST releases their newsletter, if you want to sign up in supertalents newsletter, check their home page and you have to look at the right side
Source:DDR3 mobos will ship in mid 2007