Apple has changed the membership for Mac Developers with new Mac Developer Program which only costs $99 a year, a new development program priced similar to iPhone Developer Program. Member with this new program will receive technical resources, support, access to pre-release software, developer forums and more, all for just $99 per year.
Previously, Apple offered multiple tiers (ADC Select Membership, ADC Premier Membership) at significantly higher prices (US$499, US$3499 per year) but also included hardware discounts and other perks to membership. Existing ADC members accounts will continue as is until they expire, at which time members can then join the new $99/year program. ADC Premier, Select, and Student Memberships are no longer available for purchase. The new Mac Developer Program is the only program currently available to Mac Developers.
related link: ADC membership Benefits & Resources.