Is there a way to merge two iCal calanders

I have an iCal Calander that I was using on my Mac Pro for business appointments and the like. I had some difficulty with that computer which kept me from being able to keep up my entries into the iCal database, so I started to use the iCal application on my MacBook Pro. When I was able to resolve the OS problem on my Mac Pro, now I have 2 iCal databases that I would prefer to concatenate.

Any help would be greatly appreciated!

rseckendorf