How do you switch applications in mac osx when in starcraft 2?
Solution 1:
Command + M will set you in windowed mode. From there any number of methods will let you switch applications...expose, spaces, alt-tab etc.
If you aren't in windowed mode you can't alt-tab or switch between apps.
Solution 2:
In the Options under Graphics, set the Display Mode to 'Windowed (Fullscreen)'. At that point, SC2 will take up the entire screen (unlike command+M) but you will still be able to switch between applications with command-Tab just like with any other application.