Mark/Space has announced the availability of The Missing Sync for hiptop, new software that synchronizes contacts and calendar information between a Mac and the popular T-Mobile Sidekick. “The Missing Sync for hiptop integrates with Apple’s iSync to provide two-way data synchronization between a Mac and a T-Mobile Sidekick or Sidekick II. When a user clicks the “Sync Now” button in iSync, their contacts, calendar events and to-do items are synchronized between Mac OS X’s Address Book and iCal applications and the corresponding applications on their Sidekick.” The Missing Sync for hiptop (US$29.95) currently supports both T-Mobile Sidekick and T-Mobile Sidekick II.