A very easy to navigate source as of 2015 is www.religious-symbols.net. The symbols of the current major world religions are listed there as well as some not so popular or defunct religions. For a more extensive list of religious symbols and their meanings, www.symboldictionary.net is very good.
Religious-symbols.net has 12 religious symbols shown. When these are clicked on, a description of what they mean comes up. This site does a good job providing a short, easy-to-read summary of what these symbols mean. The write ups for each symbol are not extensive, but they contain enough information to give the reader a basic understanding of what they mean.
Symboldictionary.com has a more comprehensive list of religious symbols and their meanings. At the home page, click on the tab at the top that says "A Visual Glossary of Religious Symbols." On that page, symbols are grouped into categories or what religion they belong to. Just click on the symbol to see a full description of it.