MobileFinder (strictly “Finder” in the iPhone’s springboard view) is a filesystem navigator and launcher for use with iPhones which have been jailbroken. (see http://iphone.fiveforty.net/wiki/index.php/How_to_Escape_Jail )

Features:
Filesystem navigation
Icons differentiate different filetypes
Copy, Move, Delete operations (requires that /bin/mv and /bin/cp be installed)
Application Launch (Prevents Springboard from coming back if launching GUI app with no exit button)

http://code.google.com/p/mobilefinder/