MonoTouch is always mentioned along with C#. Are the framework and toolset actually limited to C#, or do other CLR languages like IronRuby and F# work as well?
It's not limited to C#, but there are a few caveats to running other languages:
Delphi Prism is known to work - their MonoDevelop addin even has MonoTouch support. Other statically compiled .NET languages should generally be fairly easy to port.