Data formats
- FILExt: The File Extension Source
http://filext.com
the file extension source. Here you'll find a collection of file extensions; many linked to the programs that created the files. - Wotsit's Format: The Programmer's File Format Collection
http://www.wotsit.org/
This site contains file format information on hundreds of different file types and all sorts of other useful programming information; algorithms, source code, specifications, etc.