Its eassssssssyy, LOL

Guitar
Amp or pedal
big guitar-to-amp cord 1/4 inch
smaller cord that fits in the input in your computer
a converter(adaptor) to connect the big cord to the smaller cord
You also need to download a program to record it.
go here
http://
download this program
FREE ACID XPress (top right hand side)
heres the exe link
http://dspcdn.acidplanet.com/acidxpress.exe
This will keep you busy for the next month.
BTW join acidplanet and practice uploading your new tunes.
Happy Recording

The line-in is a stereo input. You really need a mixer or DI box between the guitar/pedal and the line-in of your soundcard. Look at this link for the details:
http://homerecording.com/sound_card_basics.html

You might be able to find a good used mixer just make sure it is not noisy. Yamaha, Mackie, Soundcraft are good. Behringer is cheap but should work OF for your needs.

If you have to spend more than $100 dollars I woud say look at some USB audio interfaces and forget about the PC soundcard. Interfaces come with inputs for instruments and mics. There often packaged with the recording software too. The sound quality and flexibilty they offer is worth the upgrade. It is definitley more affordable to get into recording on the PC than it was 5 years ago.