Simple function annotations like

  def foo(x: int) -> str: ...

have been available since 3.0, and editors like PyCharm already use them for typechecking.

For new PEP 0484 features like generics, MyPy supports Python 3.2 and up, but PyCharm support seems to be work in progress: https://youtrack.jetbrains.com/issue/PY-15206

https://github.com/JukkaL/mypy is the/one implementation of a static checker that conforms to PEP 484. (Naturally, as far as I know, JukkaL with mypy almost singlehandedly inspired the PEP.)

You can use it today if you want to, there is already language support for adding your own type notation.

And if you don't want to create your own you could use https://pypi.python.org/pypi/obiwan

I guess this will be in Python 3, so probably never! :P