What is commonly used for encryption over a simple Socket communication

I have X interfaces to Y computers that communicate over a public network (Think colleges and libraries). I am researching the common industry standard data encryption methods that go between us.

I know there is SSL, but I'd rather find a simple technique that is "buy once, set infinity" (trying to keep the cost of variables down). I was thinking about OpenSSL with Indy Sockets, but want to leave my mind open to other methods.

I want to find a solution that I can pass on to the vendors I communicate with. This solution should be cheap to buy, install and protect.

What is there? What is being used? How difficult is it to implement these solutions in code? What are people currently using to encrypt a simple Socket to Socket communication?

Edit: I am currently using RAD Studio 2009. However, my sellers might be using anything from Java, VS2008 for others like 4D. Whatever I find, I need to be able to convey to everyone. I would like the entire stream to be encrypted. But I am concerned that some of the older technologies that my vendors use may not use SSL. I also post this to make sure I don't miss anything obvious (e.g. Microsoft Message Queuing )