Do you mean to 'embed' the procedure into the query as one of the result fields? That can't be done, AFAIK, but if you start the procedure before you start the query and store the result somewhere, well, that's another thing and should be no problem.
In SQL2000 there are user defined functions, which can be used directly in a query - but even there, if I'm not confused by something, you can't launch sp from inside a query and use its result as one of the query output fields.