If you look under "contacts" in your gmail account, you'll see a tab labelled "groups". You should be able to place your mailing list addresses within that group and spam to your heart's content using only the group name as an email address.
Gmail allows you to use third party applications such as Thunderbird to send and receive email as well. You could also utilize that for sending mass email.
And...there are a host of places to create a list/forum (like Google Groups) that could make life a lot easier for you since you wouldn't have to manage a bunch of email addresses (remove, add, change, etc) by hand. That's a task better suited for mailing list software :-)
http://groups.google.com
http://groups.yahoo.com/
etc.
Jam it back in, in the dark.