Brushfire, the are two main methods of using SQL & FileMaker.
1. FileMaker as ODBC source. - other applications communicate with FileMaker database set to sharing with ODBC.
2. FileMaker communicating with another database that has been set up as ODBC source.
JDBC can also be used.
See this link for a starting point
Follow the links, download the guides.
There are also plugins that allow SQL statements to be used inside FileMaker to itself.
Research 'filemaker SQL' in your favorite search engine for a lot of information!
If you've already read up on the guides and have specific questions, let us know!
-- sent from my iPhone4 --