Ninth Circuit Court of Appeals judge William Alsup upheld the concept that the 'first sale doctrine' which allows the purchaser of a copyrighted item to resell it does not apply to copies acquired by a licensee rather than a buyer. Just because Psystar acquired and resold retail-packaged copies of Mac OS X, it could not rely on the first sale doctrine.
Furthermore, Apple's licence agreement did not aim to prevent competitors such as Psystar from developing an operating system to compete with Mac OS X: "Apple's SLA [software licence agreement], like the one we reviewed in Triad, represents the legitimate exercise of a copyright holder's right to conditionally transfer works of authorship, and does not constitute copyright misuse," Judge Alsup ruled.
The only part of Psystar's appeal accepted by the judge was that the sealing Apple's motion for summary judgement was overturned pending further consideration by the District Court.
You can find the court's ruling at Groklaw. Groklaw's commentary points out that this decision essentially puts to rest any suggestions that someone could obtain a copy of GPLed software such as Linux and then resell copies under a different licence by relying on the first sale doctrine.