For those who have not taken the plunge and upgraded to Pro-Tools 10. Pro Tools 9.0.6 is now available from Avid. This upgrade includes official qualification for Mac OS X Lion as well as many stability improvements for Snow Leopard and Windows 7. This is a free download for owners of Pro Tools 9.0 and Pro Tools HD 9.0. Click here to find out more!

PS: I highly recommend upgrading to Pro-Tools 10, it will be well worth your while!