The solutions I have for this are to use an HD SDI capture card from decklink. I then also have a DVI to HD-SDI converter so that I can take the DVI out from my computer and feed it into my Catalyst. The HD-SDI card is about $1200 USD and the DVI to HD-SDI converter is about $1200 also.

This is not the cheapest solution but better than USB or firewire and certainly cheaper than using an ImagePro.

Richard has been working on a new multi-input capture card prototype from Active Silicon. There is a thread started about it already. I would say that before buying the decklink, lets see how this new Active Silicon card works because it will have significantly less latency than the decklink card.