Gaming in Linux
Gaming in linux, once a fantasy, is now a reality. Apart native linux games that require no explanation, and running Windows ones in Virtual Machines that can have poor performance, and require running a Microsoft OS with all the associated housekeeping, running Windows games under the Wine Windows emulation gives you the best combination: lots of games, high performance, no hassles with viruses, updates.. But it can be still a bit tricky to install.
Actually, due to the abysmal lack of performance of Windows Vista for games, Linux (or MacOS) may be the most logical upgrade path from Windows XP.
Here are the advice I can offer from my experience
Wine Windows emulation
WineGeneralTricks
Specific games hints:
Games that I was able to run in wine without problems: audiosurf,
everyday shooter,
trackmania nations forever
World of GOO
...