Python Tools for Visual Studio turns Visual Studio into a Python IDE. It's a free & open source plug-in for Visual Studio 2010 from Microsoft's Developer Division.
PTVS enables developers to use all the major productivity features of Visual Studio to build Python code using either CPython or IronPython and adds new features such as using High Performance Computing clusters to scale your code.
IronPython is an implementation of the Python programming language running under .NET / Mono and Silverlight / Moonlight .
It supports an interactive console with fully dynamic compilation. It's well integrated with the rest of the .NET Framework and makes all .NET libraries easily available to Python programmers, while maintaining compatibility with the Python language. There also is Visual Studio tooling integration.
IronPython is an open source project freely available under the Apache License v2.0. The sources are stored on GitHub as part of the IronLanguages project.