The #1 requested feature customers sent in for OmniPlan on the iPad has just hit the App Store, so go grab it!
Tap and hold a project in the document browser to email a PDF of the Gantt chart (a full canvas, or paginated) or an HTML report (a task report or a resource report for a standalone web page.)
Instead of emailing, you might also send it over to an app like Dropbox to put it in a shared folder.
If you have an AirPrint enabled printer, you can send your Gantt chart there, too.
Head here if you were waiting for v1.1!