I've found the Ravenspiral Guide extremely useful:

http://www.ravenspiral.com/ravenspiralguide.pdf

And for anyone looking to pick up a printed text, my only reccomendation is "Melody in Songwriting" by Jack Perricone, released thru Berklee Press.

http://www.amazon.com/Melody-Songwri...1370575&sr=8-1