Karma Girl by Jennifer Estep

Synopsis: A romantic super-hero farce in an alternate reality of modern-day America where superheros and ubervillains are real and every town has their own yin-yang pair.  The story is from the perspective of a young female journalist who discovers her fiance and best friend in bed together AND finds out they're the superhero and ubervillain of the town.  In a most excellent revenge, she ousts them in her newspaper and goes on to make a name for herself nationwide by uncovering the true identities of super-characters.  She ends up in New York City and that's when the real fun starts.

Analysis: This book was great fun and well-written!  I promptly bought my own copy and put the next Estep book on my must-read list.