iphone upgrade - did it back up? If you tell iTunes to upgrade your iPhone from os4 to os4.versionupdate (example)...

Does iTunes automatically back it up before attempting upgrade?

my phone is currently in recovery mode - and I don't know whether it backed up or not (you rookie!!!)

EDIT I have browsed to the back up folder, i.e. 

C:\Users\&lt;MY USERNAME&gt;\AppData\Roaming\Apple Computer\MobileSync\Backup

There is a folder with todays date: \a6fbdb939e60771c51f18a68a41e8e0e2d230dcc - would this be the backup done before attempting software upgrade?
iTunes creates a backup of your iPhone everytime you sync it, not only when you upgrade it.

If in doubt, sync the iPhone before upgrading.

Here is an Apple Support article about the subject: http://support.apple.com/kb/ht1766