[whpalmer4]

No, kGTD isn't the only import format supported, it's just one that happened to be particularly useful for those of us who used OmniFocus' predecessor. A kGTD document is just an OmniOutliner document, and OmniFocus recognizes the particular format and skips the step where it asks you for confirmation of how it should map columns from the document into the database.

If you tell us what you are trying to import, and give an example of its formatting, we can probably make some suggestions about the easiest way to proceed. If you just have a list of actions, copy and paste is about as simple as it gets. Copy the list, click on the dot at the left end of the row where you want it inserted (make a blank action if necessary), paste, and now you've got an action for each and every row of text in the clipboard. If you have actions indented under projects in your file (with tabs), doing the same steps into OmniOutliner will get you a document that can then be sent into OmniFocus as projects and actions.