ChickLit tends to focus on one female protagonist with job or boyfriend troubles, usually in her early- to mid-twenties, and has a happy ending - she gets the man or the job she has always wanted and her evil boss/cheating boyfriend gets their come-uppance. The tone would be light-hearted or funny.
Women's fiction is either more literary or aimed at an older audience, probably focussing on marriage/divorce/kids/a more high-powered career or other more serious matters. It can also include sagas. Women's fiction is usually quite mature in tone, as opposed to the jokiness of chicklit.