Most of the ex-pats and tourists in Pattaya go to Cambodia for one reason: to extend their visa. In order to maintain a valid Thai visa, it is occasionally necessary to leave the country and then reenter in order to get yourself another extended-stay.
Easiest way to accomplish this by far is to have one of the many travel services take care of it for you. For about 2000 baht, they will pick you up at your hotel or condo in a comfortable air-conditioned minivan, handle all the paperwork, and gets you to the Cambodian border and back. They even throw in a free lunch for good measure. The entire process takes about four or five hours.
I really don’t recommend driving yourself to Cambodia especially if you have a motorbike, because the main route is on a highway that people drive incredibly fast speeds on. I wouldn’t feel safe at all driving a motorbike on it, but I guess that’s up to the individual.
If you’re going to Cambodia for an extended stay, there are also large and luxurious tour buses you can take. These are also best arranged at one of the travel companies in Pattaya. Daily flights out of Bangkok international Airport can also get you to Cambodia, if you so desire.
If you get tired of making visa runs to Cambodia, and you plan on living in Pattaya for another year or longer, I definitely recommend you look into getting on an education visa instead of a tourist visa. If you do so, you will never have to make another border run again. Instead, you only have to report to the immigration office in Jomtien every 90 days.