I have used screen sharing (via Skype and joinme), as well as tmux.
tmux provides a more interactive experience, but I find the delay to be annoying.
What are the best services and tools to use for remote pair programming?
Preferably working in Sublime Text 2, but if that is not feasable then vim is fine.
By "best" I mean:
Working in Ruby, Rails, Sublime Text 2, (perhaps) vim.
EDIT: Needs to run on OSX (preferably) or Ubuntu. Please note whether the solution runs on a local machine (and there is a way for other people to connect to it without a valid internet IP) or if the solution runs on a sever with a valid internet static IP.
For pair programming, I've used Screen and SubEthaEdit usually in combination with voice chat, such as Skype.