Ok, for the people who have played this game since it was released . .. you don't exacly need this, but for the more new, unknown people, this is a more helpful thing for you, as there seems to be some confusion on what game first(If you thought InFAMOUS 2 came before InFAMOUS 1 . . . .).
InFAMOUS is the first part of the timeline, introducing Cole and his inevitable battle with the Beast.
According to several interviews, InFAMOUS 1 took place in 2010, but after the release of InFAMOUS 2 . .. this was disproven, this was either an error from the storyline writers, the people made a mistake because the said person was caught on the spot and said whatever came to his head first, or it was originally intended to be in 2010, but InFAMOUS 2 changed it's year. Another theory is that it took place in very late 2010.
The DC Comics came next, futher expanding the story from InFAMOUS 1, taking place only a few days after InFAMOUS 1, showing a few flashbacks from just before the blast. It lasts for [according to interviews], two months.
InFAMOUS 2, takes place after the DC Comics [directly afterword], in 2011, as shown in, in-game images and mentions, and is the climax of the series, where Cole finally fights the Beast.
InFAMOUS 2:Festivle of Blood: Although it is considered non canon, it techinically takes place between the final missions, where Cole gets Ionic Storm and when he fights the Beast.(In the December edition of Game Informer, the editors stated Festivle of Blood is Canon, and takes place just before the final mission.)
InFAMOUS 3(in developmental hell) Should take place after InFAMOUS 2, we have no idea what the hell is going on with it, enjoy the wait!
Play Station All Stars
Play Station All Stars is a non canon game in the InFAMOUS series, and includes Cole as a playable character, some fans have considered PSAS to be a continuation of Cole's story and features Alden's Tower as a location as well as Ionic Vortex as a finisher.