Free ebook: 'Mobile Game Design' by Chroma Coders
I've just found this free ebook from the guys at the experimental game dev podcast show. I'm only part way through reading it myself, there's a lot of it that can't be applied to Gamesalad and to be fair the author has focused on a couple of games I've never heard of a bit too much for my liking (publicity for friend's games perhaps) but it might be worth a read 
http://www.indiegamepod.com/?p=3066
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http://www.indiegamepod.com/?p=3066