It started with Google I/O attendees and was shortly extended to a larger group, but not everyone has been able to get in on the Google Music Beta right away. Judging by our inbox today, however, another wave has just gone out. Folks who signed up might want to check their inboxes because a golden nugget could be there waiting for you. And if you need help setting it up, Rob has put together a neat walkthrough right here. [Thanks to everyone who sent this in!]