How do you back up iPhone and Mac to the iCloud service without using WiFi?
The whole point behind iCloud is to sync via Wi-Fi. It's not an option for everyone.
I have both a MobileMe account
In case you're not aware, MobileMe services terminate on June 30th, 2012.
Normally, my iPhone syncs photostream with iPhoto.
Photo Stream is part of iCloud. Without iCloud enabled, you're not syncing via Photo Stream.
"With Data" ... Compatible devices will automatically backup music, iBooks, apps, settings, photos, and app data to iCloud over Wi-Fi > iCloud Frequently Asked Questions
What can I do now?!
You can turn off iCloud services on your Mac in System Preferences > iCloud. For your iPhone tap Settings > iClooud > Delete Account.