Well, the prequel with Leah is the next planned. it really depends when I get Cora finished for because thats a joint project with Damien. I would imagine the first part of 2011 but not making any firm estimates as yet. I'll know better after Witch and Warrior and Cora are out.
for this year i'll probably just release the new updates of mm1 and 2 and then you can expect a new game early next year. when? i dunno yet, stay tuned!