If you are interested in IronPython, you should check out Matt's latest SharpDevelop addin: IronPython Integration In SharpDevelop 2.2. His blog post details the status of code completion, Windows Forms designer support, plus: converting code from C# or VB.NET to IronPython.

Please note that this is a work in progress, and that the official release of this addin will be for SharpDevelop 3 and IronPython 2.0.