It's a shame that it's hard to find introductions to Regge trajectories on the net. You might try a post on the subject (comparing them to Koide's mass formula) on my blog because I think there's a reasonable explanation, and some links to other sources of information on them: http://carlbrannen.wordpress.com/2007/12/16/regge-trajectories-and-koides-formula/
In short, Regge trajectories are not "trajectories" as most know the word, but instead are relations among the masses of certain particles.
Regge "trajectories" suggest a relation between the angular momentum and
mass of meson and baryon resonances. It's indeed hard to find some decent
information on the internet but this paper has quite a few graphs.