Here is the unpublished opinion in City of Vancouver v. Skibine (h/t Indianz). And the briefs are here.
City of Vancouver v. Skibine
Briefing in City of Vancouver v. US — Challenge to NIGC Cowlitz Gaming Decision
Here are the materials (argued last week, the panel is WILLIAM C. CANBY, JOHN T. NOONAN and MARSHA S. BERZON):
City of Vancouver Opening Brief
Lower court materials here.