The leaked "Deadpool" script written by the "Zomblieland" writers did a great and hilarious job of acknowledging the Deadpool in "X-Men Origins: Wolverine". I believe that the plans are to have the character be a new version, separate version from the one we saw.
It does not surprise me that execs are discussing a sequel/s prospect right now given that both Vaughn and Singer have now gone on record with their own ideas for where they would take us next. As I said though and still believe, I think we won't be getting an announcement on the future of the X-Men franchise until next year. I don't know why I think that but that's the feel I have on this situation right now. Maybe I'll be wrong and we'll get one sooner and those of us who dug this film can rejoice!