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.