I had the same problem with the ihome alarm volume being too loud. I used a nice idea by Jared Kipe to solve this pesky problem.
Yes it does involve taking apart the ihome, finding the speaker wires and adding some radioshack resistors to the line, but it is very easy and only took a few minutes to complete even for a novice like me.
http://www.sailbyair.com/reviews/ihome.html
climber