"Thanks for using Gmail and helping us improve the service. We're ready to expand our test to a few more users, and because you've been a trusted early tester of Gmail, we're looking for your help. Please invite a few more people who you think would like Gmail and could help us make it even better."
After a month-long dry spell, finally some more invites, . I got 6 invites total today. I've promised three of them to people on my college's Yahoo! Group. The remaining three are up for grabs. I don't expect them to remain with me for long though.