What do i need to use my guitar on GarageBand?

Could someone pls post linkage to a device that would allow me to plug in my guitar and record on garage band pls?

Ive used the mic but it sounds yukky.

Id prefer to plug right in..

thanks!

http://www.performanceaudio.com/cgi/product_view.cgi?products_id=10585

http://www.performanceaudio.com/cgi/product_view.cgi?products_id=10584

Or you can pick it up at Radio Shack.
Just plug your guitar directly into your computer with it.

Ok thanks bought it today,I can record stuff but it only plays out of the speakers when i playback,,Recording has no sound at all whilst recording..The sound levels do move however no sound whilst recording..

On the right side flyout, not sure what it's called, but it's the one where you get to select the kind of instrument and such. There you can turn the Monitor on/off. If you get feedback you will have to use headphones.

Many thanks!!!
But there is about 1-2 a sec latency!