There's as yet no English-language news about the date switch on the Eurobike website. However, German-langauge trade magazine Velobiz is reporting that the new date is tucked away in a German press release from the Friedrichshafen show.
The 2010 dates are: August 25-28, with the Demo Day on August 24.
Messe Friedrichshafen told Velobiz there was a “general trend towards trade shows taking place earlier in the year."
The date switch is also a response to the new German trade show Bike Expo, based in Munich.
It's believed Bike Expo may also move to August for its 2010 show, although Bike Expo denies such a move is afoot.