iCloud in two User Accounts

Is iCloud a function of the OS or of a User Account? I share a Mac with my wife and would like to set up iCloud for each of us, but don't want info synced from my iPhone to enter her Address Book and iCal, and visa versa. We share my Apple ID.

I haven't yet installed Lion but will do so soon, and I use my User Account on her machine as an emergency backup of my business data, which resides on another Mac and my iPhone.

I believe you will have to set up another AppleID to use with iCloud for one of you to stop the cross syncing.

Thanks Bob. That makes perfect sense.

But can I wait to set up the 2nd Apple ID until after I buy and install Lion, which I want to pay for only once (for both authorized machines).

Also, after I transition to iCloud will my children, who each have MobileMe Family Pack email addresses, continue to use those email accounts until the end of MM next June. In other words, once I transition to iCloud does my MM account 'go away' ?

Thanks.

I have a family MM account and transitioned my specific account over first, then each of my family accounts over the next several weeks. ICloud on your computer is user account specific. Your files and settings will not sync with anyone else's account (even on same computer) unless you set up ICloud to do so in that user's settings.

Mini_mi, thank you so much! This is very helpful.

Is there a tutorial to show all the ins and outs of Icloud? I can't seem to find a comphrensive set of instructions.