I've subscribed to two other guitar sites similar to this one and neither one had lyrics included with the tabs. This isn't that big of a deal for me (and maybe others?) because 1) I can sing, and 2) I can't do anything else while I'm concentrating on playing guitar. Ha, I noticed one time that I stopped chewing my gum when I was playing. Maybe I stopped breathing too....lol
Did you check out your song here:
http://www.ultimate-guitar.com/search.php?search_type=title&value=I+will+follow+you+into+the+dark
I think once you learned the guitar part and you're able to play along with the actual recording of the song (from Spotify for example), then you should be able to sing along with it and sync up the chords with the lyrics.