Google-apps – rename an email address in Google Apps

To directly answer your question, no. Unfortunately it is not possible to simply convert an account to a Group.

You can follow the procedure below to migrate the mail from the account to the Group however some data will be lost. For instance the Group won't retain any of the labels / folders in the Gmail account. Additionally Groups doesn't support contacts or calendar data.

1. Rename the account
2. When the account is renamed, it will automatically be given an alias matching the accounts old name. Delete this alias.
3. Create a Google Group using the old / desired email address. As soon as the alias is deleted you can create a Google group using the same email address.
4. Use GAMME (Google Apps Migration for Microsoft Exchange) to migrate the email from the now renamed account to the Group
5. Delete the account

GAMME supports Google Apps to Google Apps migration of mail. Additional information can be found here: Migrate data from Exchange using GAMME The GAMME Admin guide (a PDF) can be found here.

It seems like this was enabled last year. Here is the blog-post:

http://googlecode.blogspot.com/2009/07/google-apps-openid-identity-hub-for.html

Note: The Federated Login Service is disabled by default for Google Apps Premier and Education Editions. The domain admin can enable it from the Control Panel at http://www.google.com/a/cpanel/<your-domain>/SetupIdp.

The OpenID URL for Google Apps is something like:

https://www.google.com/a/<your-domain>/o8/ud?be=o8