Frankly I’m not a fan of contests that are limited to one gender or the other (are there any for men only?) but the Mslexia competition offers a good prize (£5000) and is open to female writers from any country, so it’s worth mentioning. The entry fee is £25, the deadline is September 10, 2012. You can find full details at http://www.mslexia.co.uk/novelcompetition.
(Want writing advice from only the best--like Dickens, Twain, Hemingway, Fitzgerald, Austen? It's all in my newest book, "Your Creative Writing Masterclass," published by Nicholas Brealey and available from Amazon or your other favorite bookseller.)