There’s a useful article on the Timeout website, which gives you a list of places to watch the Euro2008 games, depending on which country you’re supporting.
http://www.timeout.com/london/sport/features/4990/Where_to_watch_Euro_2008_in_London.html#articleAfterMpu
Also, other venues are:
http://www.thesportscafe.net/calendar.cfm
Related forum:
http://forum.football365.com/index.php?t=msg&goto=2079781&