Xeno-canto lets visitors to its site participate by discussing and identifying unknown sounds. And, if you record bird sounds, you should know that xeno-canto also lets people upload and share their own recordings on the site.
Also, don't miss the highly informative Species Overview pages on Xeno-Canto. Available from the left frame menu, these pages offer a summary of number of species sound recordings, photos, range maps and sonogram images. See this page, for example: