My favorite is icuii. I like it because you can actually communicate with still "quick messages" and choose to cam if you want. If you just want random cam, there are groups, where several guys are jacking. You can get a free trial for a week, and see if you like it. You actually get two subscriptions for one price, so if you have a friend to split it with, the price is pretty reasonable.
Curious_Cock is right though, Skype is the best for video/audio. No feedback. Yahoo is okay. It tends to freeze, but both sites are free.
Have you tried camming on here? The messages go by so fast, it's hard to have any connection.
A lot of guys are using oovoo. I haven't tried it. You can use it for free, but if you want to multi-cam, you got to pay.
Good luck!