http://stackoverflow.com/questions/1775954/using-python-3-1-with-textmate Variable can be set in TextMate either on a global or on a per project basis. It seems some of the internals are coded using Python 2.x, therefore a global switch to the backwards-incompatible 3.x is not recommended. Project based variable can be set by opening a project, deselecting any text files, and clicking on the little i-icon in the project window. My path for Python 3.1 is:
Your milage might vary.