1. Read the release notes.
2. Sign up for a Pre-Release Org.
3. Register and watch the upcoming Summer ’12 webinar on May 16th with Sandeep and Pat.
Watch this space for highlights in the coming weeks, and bookmark the release page on developer.force.com to get an overview of all the upcoming changes, preview upcoming related events, and to catch things like the YouTube recording of the webinar once released. Break out the sun protection, developers, this release is looking pretty bright.