Does it still run? Is it just that the rpms fluctuate all the time? It would really help if you told us the code it was throwing for the check engine light. Lift up you passenger carpet, turn your key to ON and count the number of blinks your ecu lets out. I'm willing to bet its a code 14 for you IAC valve.
Here's more info on what i mean:
http://honda-tech.com/zerothread?id=468260