If you are like me, when armed with a laptop and a cell phone, the world is your office. However, one thing that must always be addressed is making sure you have the most up-to-date files on your laptop, and that those files, once modified, can be easily updated to your main machine in the office once you get back. There are commercial products on the market that take care of that for you, such as PCLink from LapLink Software, which will run on Windows 2000, XP, or Vista, with 32Mb of RAM and 10Mb of hard drive space. If your operating system is, for some reason, older than Windows 2000, there is FileMover, which works on Windows 98SE, NT 4.0, and Me. PCLink sells for $39.95 and is from a company that has been publishing software like this for a long time.
However, if you would rather go the free route, or just want to try out software like this to see if it is useful, Microsoft has come out with a PowerToy in beta called SyncToy 2.0, but it only runs on Windows Vista and XP machines with 256MB RAM (512MB RAM recommended, and we all know what that means!), and 20Mb of hard disk space (twice as much as PCLink needs). It was developed in conjunction with Windows Home Server as a way of synchronizing multimedia files, such as pictures and music, to desktops and laptops on the home network, but can certainly be used in the business context. One downside is that it is in beta, which means that it is still somewhat a work in progress. On the other hand, it is not the first release of the software, it being version 2.0. Also, it is one of the Windows PowerToys, which have never been officially supported by Microsoft, but have nevertheless been widely used. It can be downloaded and installed for free and, if you have the requisite hardware and software, it is worth a try.
On the other hand, if you just need to take a few files with you to work on off-site, there is the Windows Briefcase feature. This is a special folder that you create on the mobile device (whether it be a laptop or a flash drive) to which you drag and drop the files that you need. Once away, you work on those files directly out of the Briefcase itself, and then perform an Update when you get back. Use of any of these programs will help you take your work anywhere, while making sure all of your data, in every location, is up-to-date.