Nickelodeon wants to start production on new Spongebob episodes in 2004 after the movie has been finished. It's up to Hillenburg as to whether or not he wants to continue work on Spongebob after the movie. No new episodes will be made until after he finishes the movie, if they are going to be made at all. Hillenburg doesn't want to split his creative time between the show and the movie. The movie is more important at this time to both the crew and Nickelodeon. This info comes from Nickelodeon executives. It has been common fan knowledge for a long time that new episodes are on hiatus due to the movie and may not get made unless Hillenburg wants to make them.
FOP is not being cancelled. In fact, work has already started on season 5 and they just finished season 4's episodes. They are working on the second FOP movie that is coming to theaters. Mr. Hartman is simultaneously working on another project, Danny Phantom. Steve Marmel, a writer for the show, is also working on another project for Spike TV. Mr. Marmel and Mr. Hartman have been in contact with the webmaster of fairlyoddparents.net where I read this information. Plus, there have been numerous other reliable sources indicating the plans of the crew to do other projects and Nick's hopes for FOP.