I've got quite a few bookmarks of very good online field guides for salamanders. Some are focused towards school-age children such as [the Yahooligans! Animals Page on Amphibians] while others are a good resources for just about everyone like [eNature.com] . [An Online Guide for the Identification of Amphibians in North America north of Mexico] produced by USGS Northern Prairie Wildlife Research Center provides an extensive list of salamander species with identification information and photographs for many species.