Oh, it's still there, I saw it just the other night, under "attack an object" or something. Somebody will give you a page number in a minute, I'm sure.
That's where it used to be in 3E; that was the exact section I looked in. Looking at the SRD now these rules seem to be part of Disarm or Sunder, as others have mentioned. I dont have my 3E PHB here to see whether this is a change to the wording of those actions or not.
Anyway, since I am wrong I guess I'll have to pick a new "latest discovery". (Perhaps I'll be wrong about this one too?)
Latest discovery: There is no more chance to hit your friends who are engaged in melee with an errant missile. Firing into melee used to be a bit risky, but now it seems you just take a straight -4. Huh.