Watch the Learning Songs online guitar lesson by Rich Maloof from Acoustic Guitar For Beginners
This clip explains the elements you're likely to see on a page from a guitar book. There are a number of styles for presenting these elements, but most include the same information. Some you need, and many you can just ignore for now.
Alternate tuning (if relevant)
Time signature - look for songs in 4/4
Chord names, and sometimes chord grids, above Music and lyrics
Standard Music notation