Chamber of Commerce of the United Stated of America, et al. v. WA Drew Edmonson, et al., US Court of Appeals for the 10th Circuit, February 2, 2010 [upholding the majority of an injunction against an Oklahoma anti-illegal immigration law, but permitting the state to enact a provision requiring businesses to check their employment roster against a state list of eligible workers through a pilot program].
Reported in JURIST's Paper Chase here. Latest commentary available here. JURIST has more on illegal immigration.