Unlike previous Market updates that might roll out at random times to your HTC EVO or other Android device, the new update is evidently completely server side. Unfortunately, it once again rolls out to you whenever Google feels like giving it to you.
Yes, as usual we're left wondering when the update will come to us. There is no stated rhyme or reason as to why some get it immediately and some don't, so although the Google Music floodgates were completely opened today, the water might take some time to get through them.
As the new update is not showing on any of my EVOs yet, I can't tell if there has been any integration with the Google Music player, which previously would only let you shop for music using Google Shopping (where you could order a CD).
The Android Market web page has already been updated to reflect Music and any purchases there are immediately available in the Google Music player, so all we're waiting for at the moment is the complete integration of the mobile platform, where most of the music is probably going to be played.
This is one of the few times where you can't just download an .apk and install it to get ahead of everyone else. This update will just show up at some poin, hopefully sooner than later.[Android Police]