You need to buy Bitcoin first. Once you have $20 of Bitcoin load it into an exchange that takes Bitcoin and trade. Apparently cryptsy is bogged down with orders

You need to buy Bitcoin first. Once you have $20 of Bitcoin load it into an exchange that takes Bitcoin and trade. Apparently cryptsy is bogged down with orders, so I would suggest http://bter.com/ http://bter.com/ which has been working quite well.