I'm researching how to best extend a C++ application with scripting capability, and I am looking at either Python or JavaScript.  User-defined scripts will need the ability to access the application's data model.  
Have any of you had experiences with embedding these scripting engines?  What are some potential pitfalls?
Have a look at angelscript
simple and easy to embed, c/c++ like syntax. free and corss-platform. u can get start in a few hrs.
Embedding a scripting engine in C++