The most common problem is the aluminum shift tube in the steering coulumn breaks. There also is 2 torx headed bolts that hold the shift lever at the base of the column that come loose or fall out. You can check this by watching the base of the column where the cable is hooked up. Wiggle the shift lever, and watch to see if the cable moves at the same time as the lever. If the bolts are loose, tighten them and try again.
If they do not move in unison,and the bolts are tight. The shift tube is broken in the column. It is also common for the bushings the tube rides on to be bad.
Autozone have some popular workshop manuals for free on line once you register (for free) on their website http://bit.ly/autozone_repair_info. and get an online repair manual subscription. There are two companies that independent auto repair shops "buy" their information from that offer a very reasonable service to do it yourselvers. You can get a one week subscription or year subscription very cheap. The information is year make and model specific repair procedures, service bulletins, component locations, wiring diagrams ect.... great quality information same as the professionals have,much better than generic workshop manuals from parts stores and much cheaper than the factory manual try Alldata which is very easy to navigate http://bit.ly/AllData_Repair_Manuals_Online or Mitchell on line http://bit.ly/Mitchell1_Online_Repair_Manuals and get an online repair manual subscription.