Wow... everyone here pretty much "hit the nail on the head." I completely agree with every post on here and would just like to reiterate that going to your local real estate clubs can be a huge help.
I started by attending one of these meetings and picking up as many flyers and business cards as possible. Not only did I get a good sense of what buyers were looking for by noticing the similarities in the properties that were being marketed by the wholesalers, but I knew where to start if I was going to do this myself. I also checked out their websites to see what kind of marketing they were doing online and how their sites were set up.
Once I went to a few meetings, read material on wholesaling, and networked with other wholesalers, I teamed up with one of them and learned the business for free. After a couple of months I sold one of their deals and earned a referral fee (a nice one too!). This was the best way for me to break into the business since I was still working a full time job and could not afford to drop everything and jump in head first.
After I felt comfortable enough, I started doing it on my own. We still work with each other (most wholesalers do), but it's nice to be out on my own. It's a great business and a perfect way to get started in real estate. Once you make some money, you can start buying some of these deals for yourself to flip, lease-option, or whatever.
I wish you all the best in your real estate endeavors! Oh, and have a great time while doing so.