I am visiting NASA's Marshall Space Flight Center (http://www.msfc.nasa.gov/) this coming week. I will present some of the methodologies that I have developed for the computation of Earth-Moon trajectories. The methodology works very well on paper, and the few implementations that I've done so far, work very well in the computer too. I mean to write a general purpose code that can assist in mission design, but I have not started yet. I will keep you all posted.
If you are interesting in contributing (with code) to the software effort, please do not hessitate in contacting me.
More details about the research effort will be posted here and in my website: http://www.andrew.cmu.edu/user/jarrieta/