Avoid C Corps, but S Corps are great. I prefer them to LLCs. With an LLC every time there's any change to the ownership you have to reincorporate. With an S Corp you just buy/sell shares of stock to bring on or drop an owner.

It's best to talk to an accountant and/or lawyer before you incorporate. But once you get the all clear you can incorporate pretty easily with one of the online services. We used bizfilings.com for one of our businesses and some of the other services for the other business.