I have an iPhone 4 and I tried charging it on my iHome but it didn't work. It plays music off my phone just fine, and when I put my iPod touch on it the iHome charges it.
Why is my iHome not charging my IPhone?
There are a lot of different iHome's. Is it the one with the charger in it? If so then I would go get it checked out at your local electronic store (A.K.A: Gamestop, Apple Store, etc.).
Somewhere along the way in releasing all these new versions of ipod and iphones Apple changed the way the charging works. When they did that existing docks stopped charging. They would still play, but not charge. You will have to check your exact model of ihome against your exact model of iphone to see if charging is supported. But I suspect that's your problem.