X38 is not certified for DDR2 ... but it does support DDR2
However so far the only board supporting DDR2 is only the MSI X38 Diamond, again DDR2 support is not officially supported.
X38 also have PCI-e 2.0 standard (which allows 300 watt instead of 75 watt) and I think doubles the bandwidth of the old PCI-e
regarding PS2 ports ... judging from some X38 board photos I think some will still have them ... and so does the parallel ports ...
As availability I sort of remembered Q3 is the well accepted timeframe.