The Interplanetary Transport Network (2006) [pdf]
www2.esm.vt.edu
www2.esm.vt.edu
I assume this has been submitted in response to the wikipedia article submitted here:
The article "Next Exit 0.5 Kilometers" [2] is a nice general audience overview of this stuff.
[1] http://www.gg.caltech.edu/~mwl/publications/papers/IPSAndOri...