Does Ubuntu support USB 3.0?

Yes, Ubuntu supports USB 3.0.

Linux started supporting USB 3.0 in the September 2009 release of the 2.6.31 kernel, and Ubuntu 9.10 Karmic Koala was the first version of Ubuntu to support USB 3.0.

In Ubuntu releases older than Ubuntu 11.04 Natty Narwhal, there is a bug in the XHCI (USB 3.0) kernel module that prevents suspend: Bug #522998.

apparently there is an issue : (522998)

When the XHCI module is loaded for USB 3.0 operation the system cannot suspend. Manually unloading XHCI will allow suspend to complete normally.

To avoid future suspend problems, the workaround is to add SUSPEND_MODULES="xhci-hcd" to /etc/pm/config.d/unload_module then the system can suspend normally.

Yes, it will. Current kernel does support usb 3.0, so you should have no problems using your drive.

By the way, linux was the first os to have usb 3.0 support: http://www.neowin.net/news/main/09/06/11/linux-is-first-os-to-support-usb-30