Try some "lock ease" or WD40 and see if you can with draw the key but it sounds like a tumbler has failed in the lock. To remove/replace the ignition lock the key has to be able to rotate in the ignition barrel to the accessory position in order to depress a plunger and withdraw the lock assembly. Once the lock is out a lock smith can normally repair the switch for you. For removal procedures, there is a company that independent auto repair shops get their information from, this same information is available inexpensively for people that work on their own cars.. The information is year make and model specific, covering repair procedures, torque specifications, fluid capacities and specifications, service bulletins, component locations, wiring diagrams ect.... Alldata is very easy to navigate http://bit.ly/AllData_Repair_Manuals_Online
Follow the instructions to disable the airbag if necessary to remove the steering wheel. Call a local lock smith and see if they would remove the lock for you if lubricating the lock does not work.