I'm holding out as well for the DRM-free music as well, but I think Doctor Q is right Apple is holding out for the last Tuesday in May or the very last day or May.
Perhaps Apple is waiting until the very last minute, hoping another record label will "jump on the bandwagon" at the last minute (or maybe they are already in serious negotiations).
It sure is weird but maybe they really are in negotiations with other Labels. For them it would be better to announce them all at once than one at a time.