"Chick-Lit" is defined in Wikipedia as a term used to denote genre fiction written for and marketed to young women, especially single, working women in their twenties and thirties.
According to this definition, I read a lot of chick-lit. Books by some of my favuorite authors fit the criteria :Laura Lippman, Susan Dunlap and Sandra Scoppetone, for example.
I just finished reading Death by Chick Lit by Lynn Harris, a mystery starring author Lola Somerville whose contemporaries are being killed off just as their books become bestsellers.
Although Lola is a little hurt that she hasn't been targeted by the murderer, she is also relieved, and sets out to discover the killer's identity, while continuing work on her current book, spending time with her friends without hurting her husband's feelings (and vice versa). Lola also has to constantly fight the perception that there's something wrong with what she writes.
Literary Critics do tend to use the term in a derogatory fashion, and I don't quite understand why. Jane Austen, L.M. Alcott, and L.M. Montgomery could all be classified as writers of chick-lit.
Oddly enough, the first known example of chick-lit (also according to Wikipedia)is Confessions of a Sociopathic Social Climber by Adele Lang, which was inspired by, or more likely a response to the Adrian Mole Diaries by Sue Townsend. This doesn't surprise me in the least, as one of the details I remember most vividly is that Adrian, as a library page, decided to shelve Jane Austen's books under light romance.
I haven't read Lang's book, and I'm pretty sure I don't want to. If this is the prototype of "chick-lit", I'm not surprised that at its use as a derogatory term.