New to emulators, questions about controller support.

Hi,
I'm completely new to emulators and have a couple questions. While I have a general idea what it's all about, and I'll find my way to making everything work I was wondering about controller support. Excuse my ignorance about basically everything!
I decided I wanted to play a couple of old gamecube and DS games. However, if I can't use a controller I decided it just wouldn't be worth it. I currently have a couple PC supported console controllers (wired) and hoping to get an adapter for my gamecube controller.
Is there any way I can use these? Or will they automatically work with keybinding? Is each rom different, as in you'd have to look for a version with [console] controller support?

Thank you for any help, and I'm sorry if I sound like an idiot!

If this has been commonly asked before, I apologize and would appreciate redirection to it.

There are a few options and prices very a lot.

1) The best option is the Bliss-Box http://bliss-box.net I don't care how you dice you will not beat it.
2) Most people like the 360 thing. Seems lots of people prefer that pad and it works with most emulators but not good for DX input.
3) Get an GameCube and psx adapter. These two match up to most. They can be had for cheap but you pay for what you get.

Always buy a no driver adapter and never by controller clones.