Reducing size of an .mp3?

Hi
I have about 30 sounds .mp3 at 20mb altogether
I need them to be around 10mb, is there anyway I can reduce the size of the audio files?
Thanks
Answer #1
will this link help at all ??
http://forums.afterdawn.com/thread_view.cfm/659531
Answer #2
reencode whit hq vbr