@allinfinite, you might want to have a look at how the Buddypress Mobile plugin detects mobile users and then instead of switching them to a new theme, redirect them (or whatever else you want to achieve) instead.
http://plugins.svn.wordpress.org/buddypress-mobile/trunk/buddypress-mobile.php
Also, apparently (i havent played with it, just echoing things i’ve heard so take it with a grain of salt) despite the name, $is_iphone also returns true for android, so if android and iphones are the only smartphones you want to show that page for, then that built-into wordpress function will work
See here on how to use it: http://wordpress.org/support/topic/is_iphone-documenation#post-1991224