Yes, lots of times. Most of those dreams were basically about chatting with famous native speakers. Once you get used to the language as much as I am, for instance, this is something that will start happening more often.
Yes, I have been dreaming in English even since I started studying the language. Spanish-speaking dreams have also happened with a certain frequency, even though I only started studying the language a few weeks ago. This week I started attending a French course and I must admit I am looking forward to some francophone dreams! :p
Sometimes when I sleep. I usually to talk with another person. The point is, every sleep is another person. I can't recognize the face, but we just talk each other in english and that is it. I think it's me speaking for myself.
I just dreamed once, many years ago, I didn't know almost nothing about english (and don't know yet...lol), but when I waked up, I didn't remembered nothing, any word, but I remember that I talked a lot in english in my dream.