iOS 5-Only want cloud back up iphone 4s

[phillymacuser]

So I have an iPad, iMac and now iPhone 4s. I am hoping to get an iPad 2 soon so my iPad is used only by my children at this point. So I installed iOS 5 on iPad yesterday. But I want to make sure it only back ups to my hard drive when synced and not to the cloud. When I log into my itunes account it says I have 2 approved devices currently (imac and ipad). I havent connect iphone yet but when I do that is the only device I want to back up to icloud. My question is can I decide which devices I want to talk to each other over the cloud? Especially when I am using the imac as the hub for all the devices? Also of note I did not update my OS to Lion on the imac. Any help would be appreciated and I apologize for the lengthy post.