The sequel to Hush, Hush by Becca Fitzgerald is OUT. Many people already know this, but I had to include it becuase I've been excited for this one even though I didn't even like Hush, Hush much.
A book I read two years ago called The Lost Island of Tamarind by Nadia Aguiar is COMING SOON. The Lost Island of Tamarind is about a about a brother, sister, and baby that end up on a uncharted island. Where fish fly, people live in trees, and boys are found in crates. Awesome adventure, and the sequel is called Secrets of Tamrind and it is coming out July 11th.
The popular novel Beautiful Creatures by Kami Garcia and Maragerat Stohl has a sequel that is OUT. It is called Beautiful Darkness. I'm going to go get this one.
The fourth book to the series The Mortal Instruments will be coming out April 2011. This isn't the actual cover that will be realeashed in December. Watch out for that! It is called The City of Fallen Angels.
Any more sequels that you know are coming out soon or are not very well known but are out as well? Please comment.