[h-e-w] help with auto-fill-mode

[Kevin Seguin]

i'm using auto-fill-mode when writing a text document to do automatic line 
breaking at a certain column.  this is great while inserting text, but when i 
go back and edit text, the paragraphs are not adjusted so that they fill to the 
specified column.

so, the question is, is there a way to make auto-fill-mode do this, or is there 
a better mode for editing text documents to get nice paragraph formatting?

tia,
 -kevin.