Valerie Ang-Powell has joined Crispin Porter + Bogusky/L.A. as associate creative director. The veteran freelancer and former Goodby, Silverstein art director will partner with CD/copywriter Sally Hogshead. ... Director Henry Holtzman, formerly of MPH, has signed with Santa Monica's BeachHouse Films. ... Preston Lee, formerly of Play/Santa Monica, has joined Area 51 Films as executive producer.