The Internet is a great source for finding chords and lyrics to songs. Three of the most popular and well-populated sites are Ultimate-guitar.com, Chordie.com and AZChords.com
These sites feature community updated content and allow you to search by specific artists or songs. For most popular songs, the chords are listed along with the lyrics so you can get a sense of where the chord changes fall. Many feature more than one version of a song, and you can choose the most accurate version based on ratings provided by the community. Often, you can find both easy, medium and more difficult versions of the same song to accommodate a variety of expertise levels.
Site members can submit corrections and feedback to existing songs, as well as brand new chords and lyrics of their own. For musicians who want to get more complicated, most songs also feature guitar tabs, chord diagrams that show exact finger placement on the guitar fret board, in addition to basic chord symbols.