The ‘core’ .NET languages are integrated into VS2008 – C#, VB.NET, and C++. I’m not sure about current support for J# and JScript.
But there are a number of other .NET languages out there – A#, Boo, Oxygene, F#, IronLisp/IronScheme, IronPython, IronRuby, Nemerle, Phalanger, P#, PowerShell, and more. Of these, I have only found VS support for F# (which is made by Microsoft, so no surprise there), Oxygene, A# (but only VS2005 support), and IronPython (only with external projects designed for this purpose).
But what about the other languages? Since they target the .NET runtime, I figure that it only makes sense that there would be a way to use those languages inside VS. Is there some limitation(s) of Visual Studio that prevent this? Is there a way to ‘force’ VS to compile these languages?
I suspect it’s pretty simple: IDE integration is no simple task, if you want to do it well. I would guess that most of these languages are done in spare time rather than having commercial funding. The amount of effort required is just prohibitively expensive – and not necessarily due to Visual Studio making things particularly hard, but due to it fundamentally being a difficult thing to achieve well.
That’s not to say it can’t be done, of course – just that it’s hard, and ‘hobby’ projects aren’t likely to get that level of commitment unless they’re really popular.
For Boo, by the way, you should look at BooLangStudio.