search/replace program

[Bill Troop bill@xxxxxxxx]

I know this question has been asked and answered a thousand times, but once
more please, I grow more disorganized with time not less so. I even went so
far as borrow a book from the library called "Idiots Guide to How to
Organize Your Life." Within hours, I had lost it.
But to get on with it. Has anyone got a simple program that will take
email-style underlines (i.e _underline_) and convert the first one to
 and the second to , going through the document until the end?
Perhaps it's even built into Jumbo? But I would appreciate any help, on or
off list. Thanks, Bill.