go to http://www.ebay.com
sign up for an account
make up a name and password
take pics of your art
name a price
etc etc etc
References :

go to ebay
click 'sell'

sell art.

ps, im sure tons of people have the same idea as you, i dont know how well they will sell.
References :

1. Take a digital picture of each of your drawings.
2. If you want to make sure people don't just steal the digital version, edit the pics in a picture editor and add something like "Copyright <yourname>, 2007" across the pictures. Make the text big enough to render the picture unusable as art, but small enough so the prospective buyer can still see your drawing.
3. Create an eBay account. I'm not going to detail the steps here as eBay does a good job.
4. Create postings of the items you wish to sell. Add the pictures you created.
References :

Go to Ebay's art catoegory and click link for self-representing artists. See what they are doing as to how they list their stuff (pricing, etc.) and go from there. Best of luck!
References :

You have the correct answers above concerning Ebay, go to the site, it's self explanatory.

I just wanted to let you know there is another website called Etsy, where you can sell anything handmade. It's a great site, I'll post a link for you below, it's also self explanatory, just follow the link. Good luck.

http://www.etsy.com/
References :

all you have to do is register as a seller, and start, there's a very simple guide online.

http://pages.ebay.com/artsellersguide/

good luck,
References :

Post a listing. Its not hard. the site walks you through the steps. Just take some digital images and you will be ready to go.
References :
http://answers.yahoo.com/question/index;_ylt=Ars6sDMcd1md2lRVu6eDVt_sy6IX?qid=20070625093658AA0uphN

http://www.aroundthewebaccess.com/onlinesuccess.htm

Advertise your ebay store/auctions free here:
http://www.greatebaystuff.com
References :