The next generation of linac-driven free electron lasers requires an extreme level of synchronization between the accelerator and laser systems to realize the scientific potential of these machines. The demands between synchronization between x-ray pulses, seed lasers, arrival time diagnostics, etc are pushing to the femtosecond level. Furthermore, high quality stable beams require relative stability between the linac accelerating sections of tens of femtoseconds. The approach that has been adopted to reach this level of synchronization is the distribution of timing signals over stabilized optical fiber links. There has been tremendous progress over the last few years in the development of stabilized fiber links for FELs. I will describe the present state of this development at Berkeley and the latest results in a timing system we have installed at the LCLS.