Snipplr is a public source code repository that gives you a place to store and organize all the little pieces of code that you use each day. Best of all, it lets you share your code snippets with other coders and designers.
I've put a few code snippets on there, the site is very easy to use. Each snippet can be tagged which enables users searching the site to find your snippets.
The code supports syntax highlighting and the ability to embed the code on another site or just see a plain text version so you can easily copy the code.
I nice touch is the site lets users comment on your snippets. The only negative thing I experience was you cannot make changed once you've posted a snippet so if you've made a mistake there is no way to rectify it.