One handy feature on our Windows Phone devices is Internet Sharing. It allows you to share your cellular data connection over Wi-fi with other devices (laptop, tablet, etc.).
The bad thing is that carriers usually charge you for this service or limit the number of devices that can be tethered (which make no sense seeing that it's your data). We've been tipped that AT&T has made a change to the guest or device limit they impose on their Internet Sharing settings.