CCL: VASP:how to calculate phonon spectrum ?

 Sent to CCL by: "Guanna Li" [gnli*]
 Dear CCLer,
 dose anybody have some experience in calculating phonon spectrum by VASP?
 could anybody please give me an example of the input file or recommend another
 opensource process ?
 Thanks in advance!
 Best wishes
 Guanna Li
 Email: gnli(a)