All I remember is the famous quote: "Disco Stu don't advertise." Any help?

google:

Disco Stu was introduced as a one-joke pony back at the Evergreen Terrace rummage sale. Homer, looking to move some merchandise, was willing to sell his rhinestone denim jacket. Unfortunately, while using his Rhinestone Nights Fashion Gun to rhinestone in "Disco Stud", Homer ran out of the precious gems and was left with a garment that read "Disco Stu". A friend suggested to Stu - a lover of disco music and the 1970s - that he should buy the jacket. Disco, in a line that will live forever in infamy, responded by saying, "Disco Stu don't advertise!"

I pretty sure it is the one where George Bush moves in as the Simpsons neighbor.

Frank is correct.

http://www.snpp.com/episodes/3F09.html

[3F09] Two Bad Neighbors

Ned: Now, folks, nothing spells "fun" like rhinestones on a dungaree jacket! [holds up "Disco Stu" jacket]
Man: Stu! You should buy that!
Stu: Hey: Disco Stu doesn't advertise.

more info: http://www.snpp.com/guides/discostu.html

[off topic]

Randy,

Check out the update in this thread.

Couldn't email ya.

[/off topic]