Advice needed: Where do I start with development (RAD)

[Craig Carver]

Have you looked at Mono? www.go-mono.com  It's a dotNET C# compiler with 
linux, Windows and OSX engines.  It will require that the mono runtimes 
are installed on the target machines, but that's not much different than 
the NET requirements.  If you're used to developing in windows, there's 
sharpdevelop www.icsharpcode.net/OpenSource/SD/ 

Check it out, it might just be what you need.