Hm, I honestly can't think of a difference, but in different scenarios, I say different things. If someone suggests a plan, I'm more likely to say "Sounds good to me." If I don't put "Sounds" in front, I'll simply say "All right by me." I don't think you would ever say "Sounds all right by me.". nor can I think of a time I said "All right to me." without "Sounds" or "That's" in front of it. Maybe that's just me though. Other common phrases that have the same meaning are "Works for me." or "Fine by me." I hope that was helpful.

In realty you will hardly ever hear "all right to me". It is extremely rare to hear, at least where I'm from (California) "All right by me" is an expression that expresses permission. If someone says, "I'm going to take the car", the recipient of that statement would say, "all right by me" essentially giving permission to the person taking the car. If someone were to ask you, "is it ok if we have pizza for lunch", you could say, "it's all right by me". It's basically the long way of saying, "yes". Hope that helps

I would say "That's all right by me." but I wouldn't say "That's all right to me."

It's covered quite well here: http://forum.wordreference.com/threads/fine-all-right-ok-good-preposition.1025027/