I have a Iphone4. Trying to update from 4.3.3 to IOS 5 or 6. There is no 'Update Software' button under Utilities/General. Tried updating using Itunes but it comes up 'The Iphone software update server cannot be contacted' ????

Are you behind a proxy server or something? You will need to use iTunes to update from iOS 4.x to a later version. Something is blocking iTunes; are you on a home or work network?

iOS 4.3.3 doesnt have the "Update your Software" tab so you will need to go to itunes and back up your iphone then restore your iphone and it will download the latest iphone software (6.1.4) if you dont want 6.1.4 download your current version and hit shift on your keyboard (alt if your on Mac I think) and click restore iphone and find your downloaded software 4.3.3 then download iOS 5 or 6 and do the samething after your phone boots up from restoring it to 4.3.3.

The ability to update over the air is a feature of iOS 5 and above. You will need to connect your iPhone to your computer and update the iOS via iTunes.