
Best programming language to code RS related programs in?
If you're adamant on using .NET to make bots, then look into compiling for the Mono framework. Mono is a framework similar to .NET which allows some .NET applications to be run on Unix platforms as well as Win32 platforms.
If you don't want to go through the trouble, you could always buy Govind's C++ ebook and learn some of that, but develop in Qt instead of Visual Studio. I'm fairly certain they allow a cross-platform compilation option as well.
However, if you're looking to code something more complicated than clickers, typers and color-finders, I'd go with what Covey says and use Java. It has all the things necessary to make a good bot since both the game and the program would be made in the same language. Interaction would be easy.
If you want to make something just like a clicker or other simplistic bots and don't want to go through the trouble of learning a language as complex as C++ or Java, you can always go with Python or REALbasic. The disadvantage of REALbasic is that it's not widely known and you have to pay for the IDE. The advantage is that it's cross-platform and has identical syntax to VB. The disadvantage of Python is that it could be a little tricky if you're not already that experienced with programming...Its syntax is sort of VBish but is unique in many other ways, which makes it a bit tougher to get the hang of.