As part of the move to the “Oracle way of doing things”, GlassFish and its add-ons (the GlassFish Enterprise Manager, now rebranded as GlassFish Server Control) are now available from Oracle’s onestop download site edelivery.oracle.com. Once you’ve logged in, follow this link (or click on the image) to get to the list of Sun downloads.
Until the release of Oracle GlassFish Server 3.0.1, the downloads still use the older names. There are 4 downloads for the add-ons, three for v2.1.1: SNMP, Performance Advisor, and Performance Monitor (description, docs) and an additional one for GlassFish v3: Monitoring Scripting Client (description, docs). These add-ons were previously only accessible to paying customers. Now you can download them for an evaluation and in the case of the 3.x add-ons, they will be bundled in the next 3.0.1 version.