For those who missed out on the last round, MS just announced that they will be adding another 25,000 beta testors in October.
So be looking for your E-mail and have those credit cards ready!
Here is the quote.
"You can also expect more games to play and more gamers to play against. (We're adding 25,000 Beta Testers in October.)
With the addition of Beta Testers, we're also adding new games to the Beta. We're sending out the online-only Beta versions of Whacked!™ and MotoGP™, on the house, free of charge. So watch your mailbox. You can also keep tackling and pummeling in the Beta - you can purchase Sega™ NFL 2K3, (available in stores now). And of course, the fierce action of NFL Fever™ lets you play hard and try to advance your Gamertag in the rankings. "