Is a 2011 50p with 2012 olympic worth anything?

Yes, it is worth the face value - 50p

In October 2010, The Royal Mint released 16 of the 29 designs, 2011 dated 50p coins. The remaining ones are to be released at the same time this year. In total there will be 81 million. Sorry, it's not worth more than 50p :)