You can search through the VBA code in your project by opening the code
window, and choosing Find on the Edit menu. The find dialog lets you specify
the scope of the search.
If you are trying to find the tables, queries, forms, or reports where a
particular field name is used, see:
Where is a field used?
at:
http://allenbrowne.com/ser-73.html
The article also contains likes to some commercial search utilities.
