Not sure if it is the check engine light or the SRS (airbag) light that must be reset at the dealer. You might want to check 3si.org/forum or us3s.com/freeforum for more info. You may be able to reset it by unhooking your neg(-) battery cable for 10 minutes. That reboots the ECU and may clear the CEL. I am not 100% positive it will clear the CEL though.
http://www.us3s.com/freeforum/showthread.php?t=3292
Here is a thread that tells how you can check the error codes yourself if you have access to an analog volt/ohm meter or make one with Radio Shack parts.