Just like the Fedora Graphics Test Week and the Fedora power management testing, they're looking for as many people as possible to fire up their latest Fedora 15 Live DVD/USB/CDs to see how well GNOME 3.0 works for you.
They're looking to catch any last minute bugs and other issues that can be worked out within the next month. To fully help out, ideally your hardware needs to support compositing so you can actually run the GNOME 3.0 Shell with Mutter. This leaves it to Intel, ATI/AMD, and Nouveau users.
The Fedora developers are particularly interested if you use multiple displays, many storage devices, optical media, WiFi/Bluetooth adapters, and various other non-standard configurations.
They'd like your feedback on test-cases ranging from using the Totem movie player to running non-GTK applications, using search, running the GNOME Terminal, and anything else you can do.
Even if you're not a Fedora user day in and day out, since Red Hat's engineers contribute heavily upstream, this will end up benefiting all GNOME-based distributions and just not Fedora.
More information on the GNOME 3.0 testing for Fedora set to take place this Thursday, see this Fedora Project Wiki page. Our friend Adam Williamson has also blogged with more details.