Fairy Tail episodes dubbed in English can be found on Funimation, on Hulu and on Dubbed Anime HD. Two of the sites listed require a paid subscription.
Funimation and Hulu require a paid subscription to watch Fairy Tail, but Dubbed Anime HD is free. Hulu and Dubbed Anime HD only provide the dubbed version of the show, but Funimation also includes a subbed version in addition. New episodes are also uploaded to Funimation on a regular basis: Fridays at 10 p.m. Eastern Standard Time. Hulu also updates on a regular basis, with episodes airing seven days after their original Japanese airing.