[Lizard]

You can configure this in the Settings for OmniFocus (at the bottom of the home screen). Scroll down below the "In Contexts, Show" settings to "Synchronization". Choose iDisk and enter your username. The path should default to Documents. (If you want to put it somewhere else, you'll have to create the folder manually on your iDisk from your Mac before using it for syncing.) It'll prompt for your password and then should just work. Let us know if you run into any problems.