A few days ago, 11.04 just went final and I am sure many of you are as anxious to upgrade it as me. I had several VM still running 10.10 and this seems to be the right path to go.
While its not rocket science, the most important thing to remember when you want to perform an upgrade is to ensure you download the right ISO. In this case, you can only use the alternative CD from here:
Then the rest of the instruction are more or less the same as before, but the exact details can be found here:
Also note that only direct upgrade from 10.10 is supported.