If you have MS Access database(or project ADP) and it is used SourceSafe for version control,
the simplest way to search VBA source code is to use Visual Studio “Search in Files” function pointed to <path>\YourDatabase.scc folder.
Note that it will also search form and reports properties and controls declarations, which can be quite handy.
I am using it with Access XP.
May be, latest virsions of Access have integrated search, similar to VS.