I am trying to install 11.10 and it keeps getting stuck on the "configuring target system" step. I originally downloaded the program to a USB drive and copied it to the desktop for installation.
Just to point out: It is possible to install Ubuntu without burning to CD/DVD or via USB drive if you're using a Virtual Machine (eg. VMWare Player/Virtual Box/etc).
I had the same issue where installation froze at "configuring target system". In my case, waiting 12 hours did nothing to resolve the issue. My resolution was to ensure my internet connection worked. I'm at work so I had to go through a proxy, set in the VMWare connection options.
It would seem that internet connectivity was the issue which, if true, is pretty sad that Ubuntu requires this on installation!
Either enable your internet connection or uncheck the "Enable Networking" checkbox in the network menu (top right) during installation.