[whpalmer4]

I'm not sure if you are proposing to use both OmniFocus and OmniPlan, or simply want to switch over to OmniFocus. I've had some success exporting projects from OmniPlan to OmniFocus, but I don't use iCal to do it.

The easiest way to move a project outline from OmniPlan to OmniFocus is to use the File->Export command in OmniPlan and save the result as an OmniOutliner 3 document. Use the File->Import command in OmniFocus to import the data to your Inbox. You'll get a pop-up window that asks you to configure which fields in the OmniOutliner document correspond to the OmniFocus fields, and the default settings work reasonably. If you have OmniOutliner, you can delete all the columns that it proposes to map to the Metadata field (aka Notes) before doing the import into OmniFocus, but it isn't necessary. Unfortunately there is no apparent way to tell OmniFocus that you want to ignore a column on import. Now you'll have all the data in your Inbox, ready to have contexts assigned. Note you won't have any dependencies enforced (have to do this action before that one) unless you arrange your data with sequential projects or action groups. You will get start dates passed across if you set them up in OmniPlan (either explicitly or by leveling).

I've not come up with a reasonable way to propagate information from OmniFocus back to OmniPlan. Hopefully OmniPlan 2.0 and OmniFocus 2.0 will have some decent functionality for doing all of this smoothly.