Go to http://www.go-mono.com/mono-downloads/download.html and click on the Beta version 3.0.6 Mac OSX image
Click on the downloaded file and you will have a new drive mounted with this contents:
If you double click on the MonoFramework-MDK-3.0.6.macos10.xamarin.x86.dmg file you should get this:
While pressing the Ctrl key, right-click on the MonoFramework-MDK-3.0.6.macos10.xamarin.x86.dmg and chose Open
this should now give you a similar popup window, but this time with an Open button
Follow the Mono installation wizard:
Until you have mono installed
Open an Terminal and type mono --version , which should look like this (confirming the correct install of 3.0.6):
Installing MonoDevelop
Go to http://monodevelop.com/download and click on the Mac OSX button
Pick the Xamarin Studio (since the mono was installed in the steps described above)
Open the installer dmg disk and drag-n-drop the Xamarin studio (humm....whatever happened to MonoDevelop???) into the Applications folder:
After install you can run the app from Launch Pad
And, it looks like MonoDevelop is now Xamarin
Update: you most likely will also need to install XQuartz. See Problem running O2's Exe on OSX 10.8 , fixed using XQuartz for more details
