It's also worth picking up a chord dictionary like Mel Bay's Ukulele Chords
A great book of straight-forward fingerstyle arrangements by Mark Kailana Nelson. Read my full review here.
A book of tricky arrangements of classical and folk tunes from the master of campanella ukulele John King. Read my full review here.
Ralph Shaw guides you through basic strumming technique and strumming in different styles. Read my review here.
Genre-hopping multi-instrumentalist virtuoso guides you through jazzy and Hawaiian ukulele playing techniques with the help of Ledward Kaapana. Read my full review here.
Jake Shimabukuro - Play Loud Ukulele Price: $14.98