I use my j2labs.net email address for everything related to development, including my subscriptions to mailing lists. Google Groups, unfortunately, makes it a bit tricky to subscribe without a Gmail address.
...but I have a solution! Just modify the URL Google uses a little bit to feed it the email address and group you are interested in.
http://groups.google.com/group/<GROUPNAME>/boxsubscribe?email=<EMAIL_ADDRESS>