Try turning (rocking) the steering wheel back and forth while at the same time trying to turn the key. Often the steering wheel lock will jam into the sttering shaft and make it hard or impossible to turn the key without relieving the tension on the lock pin.
If the ignition itself really is jammed, more than likely the whole steering jacket will need to be removed to get the lock housing removed. Or possible the lock cylinder or ignition switch (electrical component) is jamming, but this is still going to require alot of work to cure in that case. Lets hope the locking pin is just temporarily jammed.

Gilly