Not especially good, but it is, as far as I know, the only dim sum place anywhere near Westwood.

VIP Harbor Seafood Restaurant and Dim Sum
11701 Wilshire Blvd # 16
Los Angeles, CA 90025
(310) 979-3377

Correction: There is another place which was not too bad a couple of years ago.

Dim Sum Chinese Restaurant
3680 Wilshire Blvd
Los Angeles, CA 90010
(213) 739-5088