Oldsmobile Alero Ignition Switch Key Stuck

Can Anyone Tell Me How To Replace The Ignition Switch, My Key Was Stuck In The Off Position And The Steering Is Not Locked, I Was Told That...

When I Go To Turn My Key To Start My Car. Sometimes My Key Wont Turn.and When It Do Turn. Somtime It Will Not Turn Back To Turn The Car Off

We Have A 2000 Olds Alero And The Key Wont Turn In The Ignition Swith, To Start The Car, Was Wondering What Might Be Wrong, Thanks