Mono is an interesting Open Source Project, sponsored by Novell, that "provides the necessary software to develop and run .NET client and server applications on Linux, Solaris, Mac OS X, Windows, and Unix." The most recent version, 1.2.3, adds support for a Visual Basic 8.0 compiler meaning that Visual Basic applications can now be run on the Mac. The Mono project has an active Mac community already, and if you're looking to investigate you might start with this Xcode tutorial. Now, of course, the question of whether it's a good thing that it is easy to compile a VB application for the Mac is something else entirely. Nonetheless, Mono now seems to represent an inexpensive alternative to REALbasic for writing cross-platform applications.