This is a fairly common problem not only with the Xfires, but with their counterparts over at Mercedes Benz.
I had the same problem. I have a 2004 that started sticking at 67K (I now have 119K). Started out at first just sticking here and there, to the point that I thought I would crack the key. And having no decent mechanic around and with me and a husband who aren't afraid to work on our cars, I used the following information - note - if you have the time/patience/bravery, you can repair/replace the entire ignition switch unit, and not have to deal with dealers who would charge you over $400.
You can either replace the unit, or do the cheap but permanent route of grinding down the 'blip' that is causing the steering wheel to lock. We did the latter. It does not affect the steering wheel, all the alarms, lights, etc., all work fine, you just don't have the issue of the steering wheel locking when you take out the key. I didn't have to deal with new keys either. If you decide to order a new ignition cylinder, it DOES come with keys, and I think that matching the key's signal to your car is either something you can do (several links may show how to do it), or the local dealership might help. It should not cost a lot to reprogram the key - when I had to get new keys for my Toyota 4Runner, I remember having to press and hold the new key near to the computer box (I know; different vehicle, but this still should not be pricey.)
The crossfireforum.org site has lots of threads about this issue, and for the most part, the members will give out lots of information, directions - many with detailed pictures - on how to work on your car. A poster that goes by rekbah has links to a really detailed way to remove the ignition
Good luck.
This one has pictures and is great if you decide to either order and then replace the cylinder yourself, or grind down that dratted piece:
http://www.crossfireforum.org/forum/attachments/tsbs-how-articles/19226d1285817668-sticky-ignition-key-fix-sticky-ignition-key-fix_v2.pdf
http://www.crossfireforum.org/forum/attachments/technical-modifications/4322d1180104403-anyone-replace-their-ignition-switch-yet-ignition-tumbler-removal-pdf.pdf
http://www.crossfireforum.org/forum/technical-modifications/15839-anyone-replace-their-ignition-switch-yet.html
http://www.crossfireforum.org/forum/tsbs-how-articles/33074-sticky-ignition-key-fix-10.html#post504963
http://www.benzworld.org/forums/r170-slk-class/1434354-how-remove-ignition-if-you-cant.html