To update to Pro Tools 8.1.1, see the following:
To update Mac OS X 10.6 for Pro Tools HD 8.1.1 compatibility, the following update is recommended: Pro Tools HD 8.1.1 is a free update for Pro Tools HD 8 owners. Pro Tools HD 8.1.1 supports the following Mac OS X versions, on Intel-based Macs only:
To update to Pro Tools 8.0.5, see the following: To update Mac OS X 10.6 for Pro Tools 8.0.5 compatibility, the following update is recommended: Version 8.0.5 supports the following Mac OS X versions, on Intel-based Macs only: Pro Tools HD, LE, and M-Powered 8.0.3, 8.0.4, and 8.0.5 are free updates for all Pro Tools 8 owners. Pro Tools Software Versions Below 8.0.3 Are Not Compatible With Snow Leopard Mac OS X 10.6 (Snow Leopard) Compatibility Information
This article links to the latest guides that explain how to configure your computer before installing Pro Tools. Optimizing Your Operating System for Pro Tools
Supported DRM (Digital Rights Management): Adobe® RMSDK 9.1 (ePub and PDF) Download and Installation Instructions