Is it possible to use the data allowance of a phone contract on a laptop? At the moment, I have a usb dongle which I use when I need to use my laptop away from home. Instead of using this dongle, can I make my phone act as a dongle?
You can if your phone and your telco allow it.
I certainly do this with my Android phone on a pre-pay (PAYG) mobile phone account with O2. I use a USB cable (same one for charging, syncing data to PC) but you can also usually use a bluetooth wireless connection between phone and computer.
It is called "tethering"
Note that many phone companies dislike tethering as they believe netbooks/tablets/desktops use more data bandwidth than mobile phones. Phones bundled with monthly contracts may have restrictions on tethering.
If you have driver+tool that allows you to access your phone's functionality you can use it . If you are on a linux machine all you need is Blueman .