Mail Merge Field List
How to get a list of merge fields
To create a mail merge document, you need to know all the fields that are available. One way to do this is to install the Word toolbar that helps you insert merge fields in a document. Another way is to go to the following URL, which gives an XML document containing all the merge field data available for a single record:
https://na6.salesforce.com/servlet/servlet.SForceMailMerge?id=0038000000gvETe
Substitute your Salesforce "instance" at the beginning if it isn't na6, and substitute the Salesforce ID of a valid account, contact, opportunity, or other record from which you want to merge.