I use Mendeley (http://www.mendeley.com/).

The desktop version is closed source, so no chance of a port, but you also get a free online account that you can manage your references from. I haven't used it from the N900 but I can't see any reason why it wouldn't work. You can then sync to your desktop version when you get a chance.

I've just checked and the web importer works nicely from microb.

Cheers,
Jan