There is no 'automatic' means of converting a Word document to a fillable form. But it's not that difficult to do manually. See:
http://office.microsoft.com/en-us/wo...010030746.aspx
http://gregmaxey.com/word_tip_pages/repeating_data.html
Note: Although Word provides both formfields and content controls, you should not use both in the same document. Similarly, although you'll see many references to documents using formfields and forms protection, forms protection (which is needed when using formfields) is both extremely restrictive in what you can do and is not needed for documents using content controls, for which the most you might need is 'read-only' editing restrictions.