One of the major change of the "Season 2" patch is that Riot modified the summoner spells. Spells are distributed into three groups, Offense, Defense and Utility. With the new mastery trees, summoners can enhance the spells of the appropriate category with using only one point in the mastery tree. Two spells, Fortify and Rally have been removed from the game, while Surge has been added.
I hope you liked this little overview of the spells in League of Legends. If you want to know more about the new mastery trees visit my other League of Legends articles.