There's no way to compress the data, except putting it on compressed file systems. Don't EVER do this. I don't know of any third-part software out there for this either.
If you want to compress backups, there are all kinds of tools: SQL LiteSpeed, SQLSafe, SQLZip, etc. We use LiteSpeed at work. It works great.
Derrick Leggett
Mean Old DBA
When life gives you a lemon, fire the DBA.