Airhead is the first book in the series of the same name. The book was released on May 13, 2008 with two sequels, Being Nikki and Runaway, following on May 5, 2009 and March 2010. Good book!
The series mainly follows a plot where Emerson Watt's brain is transplanted into super model Nikki Howard's body. Emerson who is initially a tom-boy takes a turn to step into a super model's shoes. she also falls in love with Christopher Malloney.