By the way, you can't use 1 apple id for icloud unless you want all phones, ipads etc to have the same email, same calender, same contacts etc. I'm assuming the reason you share one apple ID is because you have bought apps using one account (i've done same thing with between myself and gf). What you can do is again create a bunch of new icloud accounts, and use these accounts on the other devices. You can STILL use one single apple id only for the apps store portion (i.e. you go to settings->store and use the shared appleID, but under settings->iCloud use the new individual accounts I have just told you to create). This way each person in your family will have their own email, own calendar (which you can allow others to view/share), own contacts etc, but you will all be sharing a single apple ID for teh APP STORE portion only.
Just to break things down further. Let's say your shared Apple ID is brian@gmail.com
Let's also say you have an iphone, and 3 other devices (iphone 2, 3, 4).
On all 4 devices you go to settings->store and enter brian@gmail.com. When you use the app store you will use brian@gmail.com).
Now create 4 icloud accounts (if using a mac update to 10.7.2 and it should prompt you to create one. On iphone go to settings->icloud and create them there on each device). Lets call these icloud1@me.com, icloud2@me.com, etc
Now you will go on your phone, under settings->icloud enter icloud1@me.com.
on the second iphone (iphone2) go to settings->icloud and enter icloud2@me.com,
etc.
Now you will have individual iclouds on each device, but share a single appleid for the APP STORE portion.