You can buy a wireless card (if you have a PC, you can boy one to fit into one of your PC-card slots that is removeable. I don't know about Macs) that will allow you to tap into any WiFi network.
If you live in an area with cable you can sign up for just a broadband account. The only other way would be if your laptop has built in wireless access and you take it to an "Internet HotSpot". You can find out if there is one near you by going to this website http://reviews.cnet.com/4520-6659_7-726628-1.html?tag=cnetfd .ld and typing in your address to see where the nearest is to you.
and if your laptop has bluetooth or an intra-red port you may be able to use your mobile phone as a modem and access the internet with this (like the data cards they are very expensive)
I use a Vodafone Live PCMCIA card (384kbps/57kbps download speed) to access my emails remotely - but it is quite expensive if you want to d/l a lot of data (and the 3G signal isn't always reliable!)