Rick Riordan's first installment of The Kane Chronicles, The Red Pyramid is set to release in book stores tomorrow, Tuesday, May 4, 2010.
Here, आप can read the first chapter of the book --
link And here, आप can hear from Rick Riordan himself what the plot of the new book will be --
link O68&feature=pyv&ad=5796588663&kw=kane%20chronicles
And his sequel series to the Percy Jackson & the Olympians titled The हीरोस of Olympus, is set to have the first book, The लॉस्ट Hero, released on October 12, 2010. That's what I have heard.
Hope this helps!!!