Start an email, put in the name, send it. Of you can put them all on a BCC list so no-one will see the other addresses. Of course you can't type in their own name in the thing that way or you'll send a letter to 30 people named Bill.
You may be able to make a form letter using mail merge where you type in a letter, and use a format for the name to link it to the cell in your spreadsheet. Check out mail merge in the help file for Word and/or Excel.