The configuration files are in the config folder which is generally under the 2.56 folder but may vary with build depending on who compiles them if grabbed from Garaphicall.org.

Also can depend on whether it is a zipped version or a self installer. Check first the installation folder and then in Documents and settings/user/Blender Foundation/ . . .

setup.startup.blend is the shipped startup default configuration file .

btfont.ttf and .Blanguages are also default files.

startup.blend should be the custom startup file.

Recent-files txt is the file list on the splash screen.

bookmarks.txt (don't know what this is for)

That is all that is in my folder, there may be more however.

Hope that helps.