The code is licensed under the terms of the open source Apache License version 2 or the MIT X11 license, at your own choice.
Also, the Mono wiki indicates you can already deploy to the App Store (which I've been looking at doing for a project): http://www.mono-project.com/MonoMacPackager
With the new release of the MonoMac add-in for MonoDevelop, you can easily turn your Mono application into a full Mac bundle, and you can also get a Mac installer for your application with all of the Mono dependencies bundled with it as well as creating Mac applications for distribution on the Apple Mac AppStore.
Is there something I'm missing?