I`ve been promising myself the Digitech `Whammy` pedal, as it is one of the coolest pedals I have tried out (you can also use it for bass, and maybe electric violin as well as electric guitar).
Not only does it have pitch sweeping effects and octave control to take your guitar down to the very depths of hell and back, to give your guitar a wider pallette of sound.
There are harmonising effects too which are in intervals of 3rds (which will give a Brian May type sound), 4ths (the Thin Lizzy/Iron Maiden twin guitar sound) and 5ths (which sounds very cool, same interval as a power chord).
Your imagination is the limit with this pedal and I cant wait to get one !!!.
Digiteh website ...
http://digitech.com/en-US/products/whammy
Hear what it sounds like ...