A Posse of Princesses is out. It belongs in the same world as Wren to the Rescue and its sequels, rather than to Sartorias-deles as do the Inda books.
However, it appears that another Sartorias-deles novel will be coming out from Norilana Press this summer. Sherwood has decided Norilana is the best bet for the prequel to Crown Duel (Firebird). Its working title was Shevraeth in Marloven Hess, and there are mentions of it under that title on the Web. However, it appears a new title is in the works, in the interest of pulling in people who aren't already fans of the Sartorias-deles universe.