Be careful of making too much of Drudge's reporting today. One of the lurid IM exchanges took place after the page was over 18. But another one clearly didn't (there is, in fact, a line where the page warns Foley that he's not 18 yet, and Foley responds that he's "just dreaming"). As NewsBusters notes, ABC has changed the wording of its story to reflect this (it now says the IMs that it has were with "two different boys who began their exchanges with Foley at the age of 16 and 17, and continued through the age of 18").
Since Glenn Reynolds seems to think that Drudge's story says all of the IMs took place when the page was 18, I guess this needs clarifying. (UPDATE: Unsurprisingly, Glenn's already amended that post.)