Despite contradicting reports, Fox has put several of their TV shows in the iTunes Music Store.
You can now purchase episodes of 24, Prison Break, Unan1mous, Stacked, and several other “Fox Television Classics” including Buffy the Vampire Slayer, Firefly, and Lost in Space for $1.99 each. However, several Fox cartoon standouts like Family Guy, The Simpsons and Futurama are missing from this current offering.
Being able to download the latest episode of 24 (that your TiVo forgot to record) is an awesome convenience for fans of the show. 24 has a major presence on underground P2P networks like BitTorrent [tutorial link] and Fox needed to make a legal download option for the show ASAP. However, for older shows like Firefly, you might want to shop around before buying episodes on iTunes. The Firefly DVD box set can be found for $20 at some places. Think about that before spending $28 for the iTMS versions.
Link: Fox shows on iTunes