wow, I just got a friend request from a "mastering lab" that offered to "master your music in 24 hours via email or myspace".   Ok, anyone who's really into audio knows that that is a complete joke.  Most MP3 files are noisy garbage audio and already super compressed.  And, MP3's are really the only way for the average Joe to send audio via the internet.  So, why would you send crappy files that are already compressed poorly to be compressed?  And then it said "download our high quality WMA files!  I recently had a band send the pressing plant a cdr of WMA files rather than a disc of WAV files I gave them.  Thank god for the person at that pressing plant who rejected the CD and told them to send WAV files.  Crazy.  So, anyways, the moral of this story is if you're gonna take the time to send stuff out to be mastered, don't send it to some place with photo's of crappy plug ins on their page.  Go somewhere like this: www.sonorousmastering.com or this: www.saemastering.com .  And don't send the pressing plant files off your Itunes!!!