Remove the plastic cover on the steering column. several screws from underneath. THere are 4 phillpis screws that hold the ignition switch to the column. Remove these, remove the switch, pull the column lock back out of the column. Now put the key in the switch and see if the switch will turn. It should turn OK with out having to work the column lock.
Hose the column lock down with WD 40 and it should work for a while.
Good luck,
Mark