The TauP Toolkit is a seismic travel time calculator. In addition to travel times, it can calculate derivative information such as ray paths through the earth, pierce and turning points. It handles many types of velocity models and can calculate times for virtually any seismic phase with a phase parser. It is written in Java so it should run on any Java enabled platform. Unfortunately, gjc, which comes with many Linux distributions, is not quite Java and prevents TauP from finding its model files. Please use Java from Sun on Linux instead.
See the project website at: http://www.seis.sc.edu/TauP