According to this piece, The Check's No Longer In the Mail, in the Washington Post, AOL's in the online bill payment business (with partner Yodlee doing the work). Not sure whether they'll be successful. From a Canadian perspective, I think it probably won't work because the banks have the "payment" side sewn up -- quite naturally.
The real work and real impact is to be had on the other side of eBPP: the presentment portion. Gotta go find out what Yodelee is up to there.