Simply copy three files to the root folder on your USB drive and edit a small text file. Anyone who finds your USB device and plugs it in is greeted with a message (see image to the left) so you can arrange its return. P2Lost is "donateWare" - feel free to make a donation.
The checksum of this file is: 7b068e20aeb684d3486815206a2b27dc (MD5)