Headphone amp thing

[LeeM]

Hey guys!

I want to build a small headphone amp thing, it needs to have clean and overdrive channels tone and volume controls, Guitar in and heaphone out.

how would i go about this? how do make the sound amplify? how do i make it overdrive? :?  

help please

[RDV]

Here's one:
http://ampage.org/hammer/files/PocketRockit.PDF

Regards

RDV