"Sam & Cat" will star Jennette McCurdy from "iCarly" and Ariana Grande from "Victrorious" as unlikely roommates
"iCarly" star "will be fine," spokesperson says, but remaining tour dates are off "until further notice"
First lady will promote her Joining Forces initiative on hit Nickelodeon series
In the movie, based on the web video sensation, Fred journeys to find his longtime crush, Judy
"iQuit iCarly" centers on rift that endangers Carly's popular web show.