I received a notice that Parallels 4 is available, and since I had recently bought a copy of 3 for the iMac, the upgrade was free. In between a bunch of other stuff, I downloaded and installed it, and I have to say I’m impressed. Version 3 upgraded my existing Windows Vista virtual machine fairly smoothly, and I’m installing an Ubuntu Linux VM right now from CD that I had lying around with 8.04 (Hardy Heron, if memory serves). Now since there is a new version 8.10, I followed the Ubuntu instructions to do an in-place upgrade.
By default Parallels allocates 512K of RAM and 34 megs of disk space for an Ubuntu installation. The Ubuntu installer said the upgrade could take some hours.