It's finally official you can read about it here, page 8 has Oracle's description of a processor for licensing calculations. So to summarize Oracle Enterprise license is $40000 or ($60000 with RAC) per processor.

When a chip has multiple cores the rules change

• UltraSparc T1 core factor .25
• AMD or Intel core factor .5
• Everthing else core factor .75

So an 8 core UltraSparc T1  8 * .25  = 2 oracle licenses = $80000
A dual Xeon server 2 * 1 = 2 oracle licenses = $80000

[ T: NiagaraCMT Solaris Oracle ]