and then run yum install mono-complete to obtain the whole thing.
This beta included the MonoDevelop IDE, which is quite nice. It supports projects, manages classes, provides code completion hints. It does not support code reformatting, import management, and the mono debugger yet. But it will get there if enough people use it.
Another piece of software that's included in Mono is IKVM, a Java virtual machine that runs on top of .NET and Mono. It allows one to write Mono programs in the Java language. It can also compile Java classes and jar files into .NET assemblies for use by C#. See Miguel de Icaza's article Java, Gtk and Mono for details.