In the episode " Marge vs The Monorail" Disc 3
there are 2 commentaries avilable. One with Writers, Producers + writer Conan O' Brien. The second is an audio Comentary with just the normal panel featured in other seasons of the simpsons. In order to recive theses commentaries Switch the audio to the commentaries with remote control
Reviews: DVD Talk also has a review of
Simpsons Season 4 by Holly E. Ordway.