I don't know if this has been posted here yet, but it was very useful to find this info out. If you own Acrobat 5.0, you can upgrade to Acrobat 5.0.5 which will run natively on OS X. This can only be done if you have Classic running on your machine. Simply start up the Update installer and choose your copy of Acrobat 5.0 in your applications folder. Once updated, you can drag the Acrobat icon straight to the dock. Once in the dock, click once and Acrobat will load straight into OS X. This saves having to upgrade your version of Acrobat to version 6 if you don't particularly need to do so.