Firefly Universe Online is a recently announced venture into an MMORPG set in the Firefly Verse.
Details are rather scant at the moment, but the developers are Indie and are working on securing the rights and licenses from Joss Whedon and Fox.
The website for the game is here. It details upcoming milestones for development and content.
As of right now, there are four planned playable factions — Alliance, Browncoats, Megacorps and Reavers; although Reavers might be getting the axe as a playable faction due to their rather brutish nature. The final decision has not been reached in regards to this, though.
The setting is planned to be the entire 'Verse, possibly to be released in a series of patches as the content is coded up and released for use.
An interview with the creator states that dialog with NPC's for missions and quests shows that it will differ from standard "find so-and-so, click through the dialog options, do mission and profit", in that you have to use the chat box and emotes in order to communicate. Thus, it is quite possible to poke an Alliance soldier or tell Niska to go piss up a rope, but you'll probably regret doing that in short order.
Travel between to points in the 'Verse will not be done via instant-travel. Players will need to obtain transport (their own ship or charter). It is hinted that random encounters and random events will be part of space travel, in order to pass the time in a fun and rewarding manner.
As of now, the developers are soliciting fans for NPC bios, jobs (basically quests), physical location information and other content. Submissions, once accepted, are compensated by in-game faction standing and in-game currency (wither Alliance Credits or Platinum). A comprehensive survey is currently up, seeking fan consensus on various gameplay mechanics, factions, and other proposed features.
Dark Cryo is also soliciting for talented fans who wish to take a more active role in helping create the game, moreso than simply giving out ideas and things - essentially, staff members that filter the above-mentioned content for acceptance.