I decided to write this howto, because I was unable to find installation and setup guide on one place on the Net.
Read it here
I spent 5 hours trying to make beryl works on Dell Latitude D600 laptop's ATI mobility radeon series 9000. As you may imagine problem was not installing and setting up beryl but how to make Ati Radeon Mobility 9000 series to work properly with either open source radon driver using AIGLX or ATI proprietary driver fglrx using Xgl. Open source driver is more stable than ATI driver is, which means that you will be experiencing much less lockings and that behavior of applications that are using video output (e.g. mplayer) is will be more expected.