Mail MergeI get comments that you cannot do mail merge in Google Apps. In fact the opposite is true - there are loads of ways to do it!
Most require you to add a Script into Spreadsheet. Do this by going to Tools and then Script Gallery. My favorite is 'Yet another mail Merge'. Just type this into the search and add it. You will get a couple of little popups asking for permission - just allow.
This one allows you to create the message to be created straight into Mail. Merge fields are in the form $%merge field%. These merge field names should be the same as the headings in the Spreadsheet where you put the data.
Once the script is added - you will see a Mail Merge option in spreadsheet. Click on this - select the message you have saved and the column that contains the email addresses and that's it.Short video below: