If you mean, when will we see a Rev B...I guess near the end of the year, perhaps a few months out from Christmas to try and catch sales then.
I wouldn't expect too much...maybe a 100 gig HDD option...maybe a slight speed bump (1.5Ghz)...hopefully a 64 Meg video card option or even standard...maybe, just maybe, an extra ram slot (but I doubt it)...likely a small price drop OR improved features for the same price...