The Usage Data Collector (UDC) is included in the Eclipse Packaging Project’s (EPP) “Eclipse IDE for…” packages for the Ganymede M4. More specifically, they are included the packages marked “UDC”. You can find them here.
The UDC is included in all the M5 packages. Nightly builds of M5 are available here. The official, “Public Access” release of the EPP packages will occur on February 26th (according to the Ganymede Simultaneous Release page).
If you download the Eclipse top level project’s SDK, the UDC is not included. You can add it to any Eclipse 3.3 or 3.4 configuration by pointing the update manager to http://download.eclipse.org/technology/epp/updates/testing to get a nightly build or http://download.eclipse.org/technology/epp/updates/0.5milestones for an integration build.