Recently interviewed by active.com.  Here are four articles from that interview.  Enjoy!

http://www.active.com/running/Articles/How-to-Make-the-Most-of-Your-Marathon-Speed-Workouts.htm
http://www.active.com/running/Articles/An-Introduction-to-Marathon-Speed-Workouts.htm
http://www.active.com/running/Articles/3-Ways-Speed-Workouts-Can-Boost-Your-5K-Training.htm
http://www.active.com/running/Articles/An-Introduction-to-5K-Speed-Workouts.htm