How to Create a Mailing List from a Google Docs Spreadsheet
The issue has always been that you have a spreadsheet full of contact information but you need to create a comma separated email list so you can paste them into the "To" section of your email and send it out.
For all intents and purposes I am going to assume that you aren't using a spreadsheet currently on google docs. If you are, just follow along. The rest of the steps are the same after you create a doc.