Wow, I never thought there would be so much DIScussion about this thread!
So far, 34 say DIZ, 22 say DIS and 4 of you say all of the letters as in "D" "I" "S". There is logic for each pronounciation. Obviously DIS (diss) comes from the home page of this site, these boards are called the DIScussion boards....and this site is also the Disney Information Station - if you have those thoughts in mind, DIS or D-I-S makes sense.
If you think of the name of these boards as a shortened Disney...then DIZ makes sense. However...there is some discrepancy on the pronounciation of Disney, which I predict is in direct relation to the area of our country in which you live.
I'm curious to know what the moderators call it.