I've just downloaded 2011 from within 2010, but when I installed it, the language changed from English to something foreign !
I had a lot of trouble uninstalling it so that I could go back to 2010, but eventually managed it and 2010 is back and in English.
I then found, on this forum, a link to download an English update, so I tried again, however, this time although it installed in English, it then came up with a warning which said the Key might have been obtained fraudulently, or something similar !!! 
As far as I'm aware my key is 100% legit and I have used it twice with NIS 2010 which is happy with it.
I uninstalled 2011 and went back to 2010 for now, but I am concerned by the message, if it wasn't genuine surely it would not have worked when I installed 2010 back in March ???