Ask TUAW: Free Icons Anyone?

Reader Thomas Mango writes: "I recently started developing a PostgreSQL database management application because I was unhappy with the products (both free and for pay) currently available to Mac OS X users. I am writing my application, PGnJ ... in Java, but I am designing the interface to be as OS X looking and feeling as it possibly can be.... I designed the PGnJ icon [pictured with this post] to look as OS X like as I could, but I'm no artist ... What I really need, are some free, regular and database-centric, icons like Save, Open, Export, Execute Query, Database, Table, Column, Primary Key, etc."

So, TUAW readers, I'm turning Thomas's question out to you: Where can he find some free good Aqua-GUI-goodness icons for coding a fully functional app that looks nicely Mac-like?