This beta is for two groups: People who want to try Jaxer RC 1.0, and, People using Eclipse 3.4 who want to test updated Studio compatibility.
Existing Studio users:
Use policy file http://beta.aptana.com/php/3.2/policy.xml, then perform a normal update.
Eclipse 3.4 users:
Follow the instructions at Plugging Aptana into an existing Eclipse configuration and use http://beta.aptana.com/php/studio/3.2/ as the update site.
New in Studio
(For more complete list, see Migrating from Jaxer beta.)