Well, it depends on what you mean by "support" :-)
Currently, OmniFocus for iPad can sync and display such documents (or hand them off to another app) when attached to actions or projects. I can create a document in Pages or Microsoft Word, embed it in an OmniFocus action or project on the Mac, and sync it to OmniFocus on iPad (or iPhone/iPod Touch). There I can either view it directly in OmniFocus, or send a copy of it to another application that has registered with iOS as being able to handle documents of that type. So far, so good.
If you only have the iPad app, however, it may be difficult or impossible to get the document into OmniFocus on the iPad in the first place. Also, if you intend to edit the document, returning it to OmniFocus on the iPad after editing is similarly problematic. If this is a showstopper for you, please send email to
omnifocus-ipad@omnigroup.com and tell them that! Omni's CEO has expressed a desire to implement the document interchange standards that should make it possible to send documents to OmniFocus on the iPad from other iPad apps, but it isn't of such of a priority that the work has been done and released to customers.