I would have to say that in order for this system of barter and exchange to be most beneficial to its' participants while serving to escape the capitalist paradigm, the system must be able to operate independantly of the federal monetary system, the world economy, and set values and worth. If we begin to say across the board, "One hour of X is worth two hours of Y", we have already failed and are merely recreating a dicotomy of haves and have-nots. The most effective system is one that requires no administration, but simply a small group with strong and diverse ties to the community willing to help bring people together who have ideas, services, and products to exchange. Individuals can figure out the worth between themselves. Once the initial labor of setting up a "central meeting place" is accomplished, the system will most likely run itself. This can be as simple as a cork board at the local library, to an elaborate web site and listserve. That is the beauty of the barter system, people can take part without a third party negotiating a "deal" for them. This is quite possibly the only hope we as communities have of escaping our classist mentality and truly seeing the value of our neighbors.
We are working on a Social Justice Center here in Carbondale, IL and I hope that a money free system can be developed for our community as well. Good work folks! And good luck to anyone working to this goal.