RSHiLib comes with three different main features.
RSHiLib features built in caching of highscore data, so all the data is not loaded every time it is requested. In addition, the signatures are cached in a way that does not generate a huge load on the server itself, allowing you to run more signatures.
In addition to containing these 3 different built in features for the script, you can also just use the highscores parsing script for your own purposes. The library is provided under BSD license, so you can use it freely for your own purposes (as long as you give proper credits).
If you are actively using this script, be sure to drop a notice on the forums.
A live demo of the highscores lookup part of the script is available.
As I worked quite a bit with the RuneScape Highscores, I've also put together a skill icon set, which includes the icons of RuneScape's skills in various formats and sizes. Basically, the icons are based on the ones from RuneScape itself, rather than the ones in the Highscores.
Personally, I don't put any restriction on using these, and you don't need to credit me for using them, because I don't really have any rights to these images. I don't think Jagex, however, will mind me distributing a set of icons intended to be used for RuneScape related websites and projects.