Can you backup your iPhone with out a computer?

I don't have a computer and I wanna backup my iPhone 4 can I do it from my phone or no I really wanna update to ios 7

Back up to icloud but check to be sure it is there and complete so it can be used if needed.

Of course you can. You can do backup with iCloud.

Same as what they say about backing up, but if you have 2.9GB of free space it won't be necessary to perform one.

You can also delete music and apps (any that you leave on the device prior beging the update will remain after update) in order to create the space necessary, then download them once the updates completed.