Who played Carly Shay in 'iCarly'?

Who played Blair Waldorf in 'Gossip Girl'? In which TV series is Blair Waldorf a main character? Who played Serena van der Woodsen in 'Gossip Girl'? Who played Michael Westen in 'Burn Notice'? Who played Alex Russo in 'Wizards of Waverly Place'? In which TV series is Walter White a main character? Who played Skyler White in 'Breaking Bad'? In which TV series is Skyler White a main character?