The Cinque Terre consists of five fishing villages perched over the sea in the region of Liguria, Italy. This page assumes you haven't walked the easy Blue trail between villages (If not, see Travel Europe's visual guide to walking the trails of the Cinque Terre).
It's best to reach the Cinque Terre by train. You'll likely change trains in La Spezia.
(The Cinque Terre map below will print to the size of your printer paper; just click the print button. Printing in landscape mode will produce the largest map.)
The numbers on the map are trail numbers. Trail markers and maps (like the one you can purchase below) will refer to these numbers.
Notice that each town has its local church. Once you've walked the Sentiero Azzuro, you might find it interesting to walk to one or more of the shrines located above each village. (Note that N. S. on the map stands for Nostra Signora):
The wide Red Path shown in the map is known as the Cinque Terre's High Path or C.A.I. n°1 path. It begins in Portovenere and ends in Levanto, following the spine of the coastal range. There is an 800 meter elevation gain (and loss!) For a good discussion of this trail, see this page. You probably shouldn't try to do the whole walk in one day; it's 40 km long and recommended for experienced walkers. The views are superb.
For more on walking or visiting the Cinque Terre, see GoEuope's Cinque Terre Travel Resources, which contains a visual guide to walking the trails of the Cinque Terre. For hiking times for each leg of a Cinque Terra trek, see Slow Travel's Trail Times.
See our Cinque Terre Climate page for historical monthly temperatures, rainfall, and current forecast for the Liguria coast and the Cinque Terre.
Here are some links to user-rated hotels and Guest Houses for Levanto and the five villages:

I'd try this Cinque Terre Map from TrekTools, a very good supplier of hard-to-find maps.

The Cinque Terre, or five lands, are Italy's five most famous villages, made famous, or overly so some say, by Rick Steves. They are reachable by train from La Spezia.
Cinque Terre Lodging