things i've heard:
UCLA: I was told my Bob Fink last week that they are having their meeting and I should hear in about 2 weeks, aka about a week from today (for musicology).
Columbia: I did not aplpy, but my friend got a call asking if he was still interested. But no formal offer.
Just in general: Different universities work differently re: admissions. Some, like (as far as I know) Chicago, accept their first round, see if they accept the offer, then work down a list, not rejecting people till they have the numbers they want. Other schools, like Berkeley, pick who they want (this year it was 5 acceptances), then reject the rest. If only 3 accept the offer, so be it, they don't let anyone else in.