How to exclude DB results based on another table

[eluser]Kyle Ellman[/eluser]
Hello.

I'm trying to return a list of records from a database, but I'm allowing users to pass on items.

There is a table of "items" and a table of "passes." The pass table contains the userID and the itemID.

I want to return a list of all items a user hasn't "passed" on.

Any ideas on how to execute this?

Thanks.