Valley residents have often bemoaned the gentrification of Mill Avenue. Up until the late 1990s, the Tempe strip was a cultural mecca of mom-and-pop shops and rock clubs. But when corporate entities started moving in, landlords started raising the rent on retail spaces, forcing small business off Mill to make way for chain stores. Mill Avenue's transformation from community hipster strip to corporate shopping district is chronicled in a new DVD, Mill Ave Inc. (Any Key Omnimedia). Filmmaker Nico