On my Desktop machine I am currently using Parallels to run Windows XP, this works well. The cost is only $50US.
On my laptop (Fujitsu P1610) I have just installed VirtualBox, which works just as well, and is free! Some of the settings to use the network card seem to be more cumbersome to achieve the same flexibility as Parallels, but actual operation is smooth. I think you can forget about trying to use Windows Vista as a `guest' in a virtualization environment running with the P1610, as the P1610 only as 1 gigabyte of memory to begin with, and Windows Vista needs 512 MB absolute minimum. Unfortunately, the Fujitsu P1610 only comes with a Windows XP Tablet `restore' rather than `install' disk. The `restore' disk will restore a disk image into the VirtualBox environment, but it does not work. This means you need to get a legitimate copy of Windows XP from somewhere else...how frustrating! The other issue is that VirtualBox has known problems with kernel version 2.6.18, which is what openSuSE comes with! As far as I can tell so far, VirtualBox works much better with 2.6.21. See `System Software ()'.
VirtualBox sometimes comes up with the cryptic error that it cannot find the secondary master device. This is the CD-ROM drive, which in the Fujitsu P1610 is an external device which might either be plugged in or unplugged. Just disable the CD-ROM setting in VirtualBox if the CD-ROM does not happen to be attached.
openSuSE comes with WINE, which allows at least some Windows software to run within the Linux environment. An easier to use version of WINE is available from Codeweavers, it is called `CrossOver'. CrossOver only officially supports a limited number of Windows programs, such as PowerPoint Viewer 2003, Internet Explorer 6 and certain versions of Microsoft Office. In practice, it works with a wider range of programs, the experience of other users is documented in Codeweaver's large database (and also in WINE's database). I myself am an `advocate' for the Chinese character writing and education software Wenlin, my experiences can be found in the application database. In particular, at the time of writing, the latest version of Wenlin will work with CrossOver, but not with current versions of WINE.