Apple is running a pretty good deal for ADC members. Until November 21, you can pick up Panther and an ADC Select membership for $500. You will also get Xcode (of course), early access to software, a developer hardware discount, six ADC TV coupons, two code-level technical support incidents, access to Apple’s compatability lab, plus all of the other goodies available to ADC Select members.
As Erik pointed out, you’re pretty much getting Panther for free with a Select membership.