Recommendations for a web app to manage beta testers

I'm running a beta test, and I need some way of managing my beta testers. Are there any apps out there that will allow me to:

• Add a number of users
• Send them messages both individually and in bulk
• Provide a method for them to send me feedback and discuss suggestions among themselves

I've not found anything that fits the bill so far.

From web app Mr. Matt

• Feedback and suggestions can be implemented using UserVoice
  Google Groups will give you all the other stuff you need.

  Mike Houston : I really like UserVoice. I noticed that Spotify is using http://getsatisfaction.com/, which looks to be a very similar service. UserVoice will give you an open forum for free, but I guess you probably want a private one for beta testing, which is a service both sites charge for.
  From seanyboy

• I use gMail for communication with a beta-group.

  To maintain privacy, the mail is sent to myself (<address>+betagroup@<host>.com) while individual addresses are hidden by entering the group-name as a bcc: (gMail then fills in the fields with all of the individual address; hence the bcc:)

  This does NOT allow for inter-group communication, however.

  I've been meaning to switch over to a private google-group for.... a year now? heh.

  From Michael Paulukonis