Mail Merge
The GoogleApps Script gallery contains several mail merge scripts. All of these start with a spreadsheet of data, but the manner in which you compose the emails can be markedly different. The body of the emails is most usually composed and saved within another sheet of the data spreadsheet. Others may pull the email body text from a GoogleSite page.


Yet Another Mail Merge
While each of these can be good in some situations, I think it's more intuitive to compose your emails within Gmail. Yet Another Mail Merge is the perfect script for this. Your email can be formatted, included images and attachments. When run, the script looks into your Drafts folder and offers them as the merge target.

Yet Another Mail Merge

Both the draft and data are held in the same spreadsheet when using FormEmailer. The script will create a basic mail window and you can add in the data placeholders. It will also allow you to send multiple emails from one row of data.