Coming later this month.
Not according to Apples page - it comes today:
http://www.apple.com/startpage/
Introducing the iTunes Wi-Fi Music Store
Starting today, you can enter the new iTunes Wi-Fi Music Store; wirelessly browse, search, preview, purchase, and download songs or albums to your iPhone or iPod touch; then immediately listen to your new music after it downloads. Once you get back to your Mac or PC, iTunes automatically recognizes the new music and syncs it with your existing library. iTunes will even complete the download of any partially downloaded songs or albums.