not 100% on how to go about that on the mac, because i have yet to acquire one.
The idea is the same though, irrespective of OS. as long as SSH and SFTP are set up on the iTouch, you should be able to connect. In a Terminal window, the command 'ssh <ipofipod>' should get you connected, then using the standard user/pass combo of 'root' and 'alpine' respectively, you can open a terminal. That should allow you to check if sftp is running, but i'm not sure which command you'd use to do this. Any ideas?
Otherwise the command 'scp' in the terminal will let you know how to go about copying files etc.
'/Applications' is the folder that you want to copy the apps to using scp or sftp. Whatever is in the Applications folder shows up on the springboard. I use WinSCP to copy apps personally, but obviously that isn't on OS X, so it won't help much.