You can watch live streaming of football on YouTube. It features live soccer matches from around the world, all of which can be viewed for free. The leagues include:
As well as football, YouTube also shows live basketball, cricket, cycling, speedway and many other sports.
Simply go to the YouTube Live Channel and scroll to the bottom of the screen where it says Live Now - Sports. This will show you the events currently available for live streaming.
Be aware that the streams sometimes don't start until just before the event or match kicks off. So don't worry if you don't see the match you want listed, just come back at the scheduled start time and refresh the page and it should show up.