The streaming method hasn't changed, all that has changed is the codec. Currently what is widely used is MP3, AAC is from the same maker as mp3.
At any rate if you want to stream in AAC check out oddcast at www.oddsock.org
AAC+ costs a bundle is only currently be supplied by one vendor. Orban's Opticodec.
The server works the same either way. You cannot list on shoutcast's YP using AAC either.