If you wish to download a copy of Macbeth to your phone or tablet, you may find copies here:
Project Gutenberg (links to .html, .epub, and Kindle-formatted versions)
Macbeth for Kindle ($.99 charge)
Macbeth for Nook ($.99 charge)
Download or listen to a streaming audio version of the play at Librivox.
An audio book file of Macbeth can be found here.
The full text of the play may be read online here.