eNature's Amphibian Species Identification Field Guide will assist you in identifying the amphibian species you are likely to encounter in your state. These online guides provide a brief description, several specimen pictures, and geographic range maps for each frog and toad species found in North America. Use the filters at the top of the page to select your state and then use the photos to help determine the species you have observed. If you are not sure which species you have found, please include a note in your Fieldscope submission form and upload pictures if possible.
Please keep in mind that being captured in a photograph is far less stressful than being captured physically! A good photo often suffices for identification purposes. If you do try to capture an animal, make sure that you know which species are protected by law and which ones may be harmful to you due to toxins in their skin.
In addition to the eNature link above, there are many region specific guides and checklists available online that may provide additional information on the amphibians found in your specific area.