The zootoolbox is a collection of open source mel scripts created by Hamish McKenzie to greatly assist both riggers and animators. During the last couple of years I have come to rely heavily on the zootoolbox and it has been an inspiration for developing my own tools. I am not an expert rigger like Hamish but I thought I would write this guide for people starting out and wondering what to do with all those mel scripts (...like I did).
First a warning. The zoo tools take some effort to learn how to set up and use. People with no stomach for the inside of a mel script should probably turn away now. On the other hand people wishing to build upon their knowlege of mel scripting will be very happy. Hamish has created well commented modular scripts that are easy to modify or to take function from for use in your own work.
Having said that, I should add that I have helped people with no mel knowlege learn to use some of these tools effectively with a minimal learning curve, so there really is something for everybody here.
I am a windows XP user so the examples I provide will be windows-centric.