Patchery is a free utility website for creating and applying small binary patches to individual files. It uses the HTML5 file API to safely read provided files.

http://www.patchery.net/patchery/about.html

It's currently in a beta state but the basic functions are available. The database is currently small but growing. You can help by testing out the website and reporting any bugs. The easiest way to get started is to follow the link above, navigate to the search page and type a common letter (like "e") into the search box to get a list of patches.

All functions except patch submission are available without logging in. There is a demo account available for anyone who would like to test out the patch submission:
demouser@patchery.net
DemoPass