Here is the opinion (100 pages).
Here is the audio of the oral argument.
And here are many of the briefs.
Indianz.com published the rehearing petitions from the US and the Arizona Snowbowl operators and the oppositions from the Hualapai, Navajo, and Hopi tribes all in one document, here.
Our previous post on this case, with all the materials from the earlier 9th Circuit proceedings (again courtesy of Indianz) is here.
From Indianz.com:

The sacred San Francisco Peaks in Arizona. Photo Deborah Lee Soltesz/U.S. Geological Survey.
Court Order:
Navajo Nation v. US Forest Service (October 17, 2007)
Earlier Decision:
Navajo Nation v. US Forest Service (March 12, 2007)
Listen to Oral Arguments:
Navajo Nation v. Forest Service (September 14, 2006)
Appeals Court Documents:
Opening Brief [Word DOC] | Reply Brief [Word DOC]
Lower Court Decision:
Navajo Nation v. US Forest Service (January 11, 2006)
Approval Documents:
Final Environmental Impact Statement for Arizona Snowbowl Facilities Improvement | Forest Service Approves Snowmaking at Arizona Snowbowl
Relevant Links:
Save the Peaks Coalition – http://www.savethepeaks.org
Coconino National Forest – http://www.fs.fed.us/r3/coconino/index.shtml
For academic scholarship on sacred sites, see Kristen A. Carpenter’s work here.