You wouldn't be able to download data direct from any dive computer I know of. The N900 can't act as a USB host (for most), and has the IR port is TX not RX - so that would rule out the rest that still use ir ports.

I'd like to be able to copy my logs from Diving Log to the N900 but it's such a niche app that I'm not going to hold my breath. (first rule of diving....)