From inter alia: Remote Printing Made Easy
PrinterAnywhere is an interesting application — it allows you to safely print documents on any printer, anywhere in the world — or to have documents printed on your computer from anywhere in the world. It’s a free download, but both you and the owner of the other printer has to have the software installed. Once you’re both up and running, you can easily print a file to the other’s printer with just a few clicks. According to the site, the print jobs are encrypted, so PrinterAnywhere is safe to use.