Guitar Voicings

what are some great books to show me some great voicings of chords for both piano and guitar?

I'm not sure what you mean by voicings, but if you want to learn chords, it's best to learn scales first. You'll then be able to form chords just by knowing the structure of the chord. You'll then become a chord master, and be able to not only play chords, but be able to improv. to a song. I would recommend a scale book like this: http://www.google.com/products/catalog?q=piano+scale+books&hl=en&cid=9083458362206486393&sa=title#ps-sellers

However, if you want to learn chords only, there are websites that can teach you as well. It's harder to improv, but if chords are all you're looking to do, check the internet for chords. Here's a piano chords library:http://www.8notes.com/piano_chord_chart/
Here's a guitar chords library:http://www.chordbook.com/guitarchords.php

Jazz voicings for guitar

Adam Kadmon: The Guitar Grimoire - Chords and Voicings $16.00 GUITAR GRIMOIRE:CHORDS AND VOICINGS - DVD Movie...

When Music Works: Modal Voicing Techniques $10.98 Bring new colors and voicings to your playing with Berklee professor Rick Peckham, internationally known jazz guitarist, composer, writer and clinician. In this master class DVD, Peckham unlocks the mysteries of modal tonality, with a series of exercises...

Chordability $11.58 Studio: Allegro Media Group Release Date: 07/12/2011 Run time: 149 minutes...