What do I need to make a MIDI Controller that has knobs, sliders and pitch/mod wheels?

[SSShadii]

I am interested in making a MIDI Controller with knobs, sliders and pitch/mod wheels.  I have never done something like this before.  What do I need as far as chips, equipment, etc.?  Where can I get these supplies?  Is there a website that sells this sort of thing?

Thanks