Crossfire can be used on any webenabled device (from Nokia to HTC phone, to iPhone to even Playstation3). It also works perfectly from any desktop (Firefox and IE) and is tended to be as lightweight as possible (minimal dependancies) in local and wan environments.
Its a PHP and AJAX based webapplication, so you just need to have PHP and a Webserver (Apache, lighttp, Cherookee or IIS) on your Ubuntu box.
You just will need to configure the config file, and might want to optimize a template to suit your need.
I think there might be someone on this forum which has already done so for the N810.
Cheers,
Tony