CHICAGO (thefutoncritic.com) -- The White House has scheduled a press conference for tonight at 8:30/7:30c, news of which has sent the broadcast networks into a tizzy. The expected 45-minute event has forced ABC, CBS, FOX and NBC to shake up their schedules with FOX's being the most disruptive.

While ABC, CBS and NBC will easily be able to plug in repeats around the press conference, FOX has been given the most headaches. With the event's likely one-hour length and 8:30/7:30c start time, there's no room for Tuesday mainstays "American Idol" and "24." Instead FOX will shift both "Idol's" performance and results shows back a night while "24" will air this Sunday at 9:00/8:00c. The moves will have a domino effect on FOX's previously announced schedule, as noted below:

Tuesday, April 13
8:00/7:00c - "That '70s Show: We�re Not Gonna Take It" (Repeat)
8:30/7:30c - "President Bush Press Conference"
9:30/8:30c - "That '70s Show: I'm a Boy" (Repeat)

Wednesday, April 14
8:00/7:00c - "American Idol: Episode 317" (Special Night)
9:00/8:00c - "The O.C.: The Proposal"

Thursday, April 15
8:00/7:00c - "American Idol: Episode 317A" (Special Night & Time)
8:30/7:30c - "Tru Calling: Death Becomes Her" (Special Time)
9:30/8:30c - "The Simpsons: Smart & Smarter" (Repeat)

Sunday, April 18
7:00/6:00c - "King of the Hill: The Incredible Hank" (Repeat)
7:30/6:30c - "King of the Hill: How I learned How to Stop Worrying and Love the Alamo"
8:00/7:00c - "The Simpsons: My Big Fat Geek Wedding"
8:30/7:30c - "The Simpsons: The President Wore Pearls" (Repeat)
9:00/8:00c - "24: Day 3: 6:00 A.M.-7:00 A.M." (Special Night)

Wednesday, April 21
8:00/7:00c - "That '70s Show: Substitute"
8:30/7:30c - "American Idol: Episode 318A"
9:00/8:00c - "The O.C.: The Shower"

Sunday, April 25
7:00/6:00c - "King of the Hill: Dale Be Not Proud" (Repeat)
7:30/6:30c - "King of the Hill: Girl, You'll Be a Giant Soon"
8:00/7:00c - "The Simpsons: Catch 'Em If You Can"
8:30/7:30c - "The Simpsons: Today I am a Clown" (Repeat)
9:00/8:00c - "Malcolm in the Middle: Experiment"
9:30/8:30c - "Arrested Development: Let 'Em Eat Cake" (Season Finale)

Note: "Not Without My Daughter," the penultimate episode of "Arrested Development" originally set to air on April 18, has not been rescheduled.

Additional changes may be announced at a later date. As for the other major networks, here are the changes to ABC's upcoming schedule:

Tuesday, April 13
8:00/7:00c - "Eight Simple Rules: Get Real" (Repeat)
8:30/7:30c - "President Bush Press Conference"
9:00/8:30c - "According to Jim: T.B.A." (Repeat)
10:00/9:00c - "N.Y.P.D. Blue: The Brothers Grim"

Here are the changes to CBS' upcoming schedule:

Tuesday, April 13
8:00/7:00c - "Still Standing: Still Negotiating" (Repeat)
8:30/7:30c - "President Bush Press Conference"
9:00/8:30c - "King of Queens: Affidavit Justice" (Repeat)
10:00/9:00c - "Judging Amy: Kilt Trip" (Repeat)

Here are the changes to NBC's upcoming schedule:

Tuesday, April 13
8:00/7:00c - "Whoopi: Strange Bedfellows"
8:30/7:30c - "President Bush Press Conference"
9:00/8:30c - "Frasier: Guns and Neouroses" (Repeat)
10:00/9:00c - "Law & Order: S.V.U.: Shaken" (Repeat)

Tuesday, April 20
8:00/7:00c - "Whoopi: Sins of the Sister" (Season Finale)
8:30/7:30c - "Happy Family: Dear Mom" (Season Finale)
9:00/8:00c - "Frasier: And Frasier Makes Three"
9:30/8:30c - "Scrubs: My Choosiest Choice of All"
10:00/9:00c - "Law & Order: S.V.U.: Criminal"

UPN and the WB will proceed with their previously announced lineups. Also note that in the mountain and pacific time zones, the live nature of the press conference may shuffle programming even further.