MP3 volume

[#1]

Hi all
I'm pretty sure I know the answer to this already (No) but I thought I'd ask incase any of you have a miracle answer...
I've got some MP3s which are about 1/2 the volume of my others in my collection. Its really annoying in the car as I'm forever fiddling with the volume.
Anyone know a wonder cure to recode them to a higher volume or am I stuffed?

[#2]

put them through Audacity, works a treat
load mp3
high light file
Effect - Amplify  try 10-20db watch what happens

[#3]

Does your MP3 player not have a volume levelling option - my Zen has an option called "Smart Volume" which performs an automatic levelling trick to keep the real volume level constant.

[#4]

iTunes will also perform this automatically upon import to a library.
I've used mp3gain before.  It doesn't actually screw around with the MP3 data, it changes the volume reference frame for the file itself (so it's easily reversable, and won't clip your music at max or min levels)
B.

[#5]

Thanx guys - I tried audacity and it seems to do what I want!
I'll also try that other proggie that you said about Barry!