You can watch episodes for free on the fox channel's website. But, I don't know how many of the episodes they keep on their site. I have had to watch one of the episodes on that site before because my power went out and I couldn't watch the show on TV so, I just waited a couple of days until they had that episode up online. http://bit.ly/TVShowsToolbar
The tv.com, oliv3r.net and tvshowservers.com are some of website where you can download TV series for free. They have the Biggest Free-Stream TV-Show Network on the internet and you can find list of over 150 TV-Show websites, all streaming full length episodes online. Get all your popular shows from around the world, updated instantly and available 24/7.
In the US the following are 2 excellent and safe websites for tv shows and movies. However I suggest you use Chrome or FF and the addon AdBlockPlus to get rid of the ad links:. You will also need a video player which plays all formats such as KM Player.