While its relatively easy to roll your own social sharing tools, especially for things like Twitter and Facebook, the tool kit below is a good set of icons, buttons, and popups for social sharing.
The page describes it as the following:
Social Share Kit is a library of decent and good looking CSS/JavaScript social sharing tools like social network icons, share buttons, floating/sticky button bar and popups.
It is open-source library hosted on github, yet licensed under Creative Commons Attribution-NonCommercial 3.0 license.
While it is licensed with a non-commercial license, it can’t be licensed for $19 for a single commercial site, or a $79 unlimited commercial projects license.
