Hi , i am new general question..

[eluser]veritascs[/eluser]
Hey, you should be able to move it into CI fairly easily. It won't be a copy paste but the learning curve will be short. You're going to have to separate all your logic out into the MVC pattern like SmokeyJoe mentions above.

First though, you should build a mini site that connects to your database (like a really simple blog or something http://net.tutsplus.com/?s=codeigniter). Once you've done that, I think you'll see how CI works and be able to go from there.