Leafsnap is supposed to be available for Android phones soon, however from what I understand the app really only works for species in the northeast US at this point (since that's where the volunteers are), and mostly trees.

A link to the list of species the app can identify is below.

Here is a link that might be useful: Leafsnap species

Thanks, Alabamanicole. Yes, I read about the region bias for the plant selections. But there is hope at least.

We need another Blanche Dean to create such a reference in Alabama. The book she wrote years ago was my first ever gardening reference.

Cool app ! Just be aware & careful that it is recording your location. You snap a pic of an extinct Dodo plant growing in your backyard you might find your house surrounded by uninvited onlookers.

One other app is Gardener's Companion Free. It finds the hardiness zone for your zip code and gives you temperature, and percipitation charts:

https://market.android.com/details?id=toto.gardenerfree

the paid version (.99) finds the zone automatically from the GPS location. useful if you wondering around taking pictures of unusual trees and want to find out their zone.

Here is a link that might be useful: Gardener's Companion Free