Adobe has provided seven how-to guide and their corresponding source files (Illustrator CS5) to highlight some of the really cool features in the latest version of their vector-based illustration software. These files are provided by some very talented illustrators, artists, and designers such as Joel Cocks and Christian San Jose. As I mentioned before, I find it interesting to see how others work, especially how they organize and think through their file structure. This is an excellent way to learn by example and can pick up some new techniques.
Download the Illustrator files, how-to guides, and if you don’t have a version of Illustrator CS5, you can download a trial version here.
(via Adobe)
designblinks 
Hello, Great Post! I am a corel draw user, and now still learning adobe illustrator.
This guide help me to understand more about adobe illustrator. Thank you very much š
Thanks Imkiki! I learned on Illustrator, but have used other vector-based programs in the past. I think seeing how some of those files are built helps you see the potential of what can be done with Illustrator. Glad you enjoyed it.