Hi...for more detail information on JIT Please see link below on techxcel.com

Here you can get details on JIT. Its working and lots more information on .NET General FAQ

http://www.techxcel.com/content/view/31/99999/

I this this will help you

Regards
Chetan Akarte

Jit: Just in time compiler is a part of CLR it will MSIL Code to NAtive

 Code. means the o/s code. as o/s dosent understand MSIL