I use VMware under Ubuntu to run Windows XP and I'm very happy with it. However, from time to time (like last week) an Ubuntu upgrade gave me a new kernel version (2.6.15-28-386). When this happens, the VMware installation goes 'castors up'.
To get VMWare working again it needs to be re-configured by re-running the usr/bin/vmware-config.pl script.
Before doing that, you need to grab updated headers with something like this:
sudo apt-get install build-essential linux-headers-`uname -r`
Accepting the defaults for everything works fine except for the location of the Linux headers. You will want to feed it something like this as the location of the headers:
I keep forgetting this which is one of the reasons I'm blogging it here.
If you are looking for a cheap way to run Windows under Ubuntu, the free version of VMWare server is well worth a look. Just remember the upgrade dance when your kernel version changes.