Here's what i've found to the original source (from another page that has scoured the web)
"Writing about music is like dancing about architecture - it's a really stupid thing to want to do."
--Elvis Costello, in an interview by Timothy White entitled "A Man out of Time Beats the Clock." Musician magazine No. 60 (October 1983), p. 52.
..but now i also see a few sites that quote Zappa as being the source as well....innnnteresting.