Now should I purchase something via itunes and need to sync to it will it not now wipe my iphone as its syncing with a blank itunes
iTunes knows that your iPhone is backed up to iCloud, and so assuming your computer has internet access, I believe it will work it all out.
You can also switch on auto-downloading on your iPhone so if you buy something on iTunes, the phone will download automatically. If you don't want this, you can use the "Purchased" tab which shows everything you've already downloaded on that account - on iTunes or another iOS device - and you can pull down a copy to the phone.
or for that matter I choose to backup for another software update mine says I cannot use the icloud for this ? same thing would happen a blank itunes would threrfore blank my phone to match?
I Cannot find the answer to this anywhere any ideas and links to back them up ?
Now you're on iOS 5 software updates to your iPhone are done on the phone, as long as you are on WiFi, under Settings->General -> Software update. Its reported they will be smaller than iOS 5 download as only the changes are sent down.
That's what the developers were reporting for the beta versions of iOS 5.
pro - on THFB - sync about 17.2mbps - BQM