With Blizzard's big push over the holidays, reducing the price of WoW and the free 10-day accounts, there have got to be plenty of new players getting close to 60. A guide to 60 was posted a few days ago, but Gamespy's new guide for people who are reaching 60 for the first time is great. It has detailed breakdowns of all the major instances, all the major quest chains, some of which start at level 52, and is generally a good guide to the PvE endgame.
I missed the Linken's Secret chain the first time around and kicked myself when I found out about it. This comprehensive guide, though helpful for experienced players too, is especially nice for first-timers.