Im a little worried about using Google Groups as my email list because I dont have control of the email addresses. Arent you worried about this?
Google Groups has an option to export the members of your group as a .csv file which can be opened in programs such as Microsoft Excel. This contains all the names and email addresses of the members of your group and can easily be transferred to any other email distribution software if you choose to do so. Its a good idea to backup your list regularly.