I recently had to dive into MOSS search crawl rules and figured I’d post some good references for myself that would my first stop if I have to do something with MOSS crawl rules again.
First things first, if you want to do some custom crawl rules specifically with FBA, you’ll need the tool “addrule.exe” from MS. This tool allows you to build an custom crawl rule in XML format and inject it into the MOSS search. Obviously this tool will need to be run on the server that does the crawling.
After downloading the tool your obviously going to want to know the XML schema for the crawl rules, so check out the following MSDN article.
With those 2 links you should be well on your way to working with some custom search crawl rules especially when dealing with FBA sites and search.