If you don’t currently have mobile broadband access and you are out the office a lot, with a need for data, I suspect you spend a good deal of time working from coffee bars and taking advantage of their wifi access, free or otherwise.
Before you head out next time, it’s worth checking out Trustive – an excellent resource which has over 30000 hotspots plotted across 75 countries on a Google Map. Very cool.
They do a pretty good deal on wifi credits too which is definitely woth investigating.
They have also just released a dedicated site for iPhone users too to find wifi hotspots if you don’t have 3G coverage.