After ten years with stored procedures I am thinking so this is not too well technique. Much better is writing stored procedures to a file and using usual tools for file's versioning. We did some tools for storing a versions inside database, but still we prefer a standard developer tools - vi or emacs like editor and plain text. The main problem of procedures maintained inside database is loss of outer formatting and outer comments. And you cannot to group procedures to modules. On the other hand - some history can be useful for all database objects - not only for stored procedures.
