It often comes down to what you want to acheive - if what you want is the experience of trying to create your own game, regardless of whether it gets beyond the planning stage, then you\'ll probably enjoy designing a MMORPG, possibly implementing a few concepts, and then moving on to other things. If what you want is to participate in the creation of a game that actually gets used by people, you\'ll most likely have to sacrifice the desire for leadership and participate in an existing project.
If you don\'t have experience or a demo, the best way to get a team together is by people who you know (and have a positive relationship with) since few people are willing to join up in a team unless they feel that it is operating at \"their level\".
EDIT:
Also, note that the \"Planeshift\" project itself involves two parts - an open-source game engine (the planeshift engine) and the game content, which is offered free of charge (but can\'t be used for your own projects). If you don\'t have programming experience, you could always try making content for your own game based on the planeshift game. Just to re-iterate though, you *cannot* use their art, maps, sounds, or game rules.
