The purpose of ds9ficathon is to encourage Deep Space Nine fiction by allowing each participant to request a story in exchange for writing someone else's request. Anyone may participate whether or not they are experienced, whether or not they have a livejournal.
More information and round one sign-ups can be found here. Sign-Ups for round one are currently closed, but watch the community for the announcment of the second round.
Need to a refresher on canon? Try: Memory Alpha - All sorts of information on Deep Space Nine and other Star Trek series. Star Trek Minutiae - Scripts for every Deep Space Nine episode.