PilotHandwriting is a free web service that turns your handwriting into a font that you can install and use on any computer.
The site - a product of the Pilot pen company - is similar to previously mentioned YourFonts, and the process is likewise similar: You print out a template, write the corresponding letters in each box, and then upload your filled out template back to the site (the video above demonstrates the process). PilotHandwriting is a touch more user-friendly than YourFonts, and it features several different methods of uploading your handwriting back to the site (including a really smart built-in webcam capture tool, a scanner or a regular digital camera). You can even test your font or correct small imperfections.
The extremely frustrating part: PilotHandwriting doesn't allow you to download these fonts. Instead, you can only compose and send emails from their website. So if you just want to play around with it, go ahead and use PilotHandwriting. If you want to make something you can actually use, head over to YourFonts. (Pretty please, will you add font downloading, Pilot?)