lambo, there are a lot of factors involved on how well a wireless router will work for your gaming needs. It has everything to do with the quality of your connection.
OOZ is correct in the fact that wireless routers are slower than wired ones, however this probably won't be an issue. You're still limited to your internet speed.
There are wired routers out now capable of 1000Mbps, but the standard is 100Mbps. Wireless routers are usually 16Mbps or 54Mbps, so yes that's quite a bit slower, BUT even the fastest internet connections these days are typically 10Mbps. As long as your network connection is faster than your internet speed, then anything more is overkill.
Now here's where your connection quality comes in. If you have a poor wireless connection (due to interference or distance or whatnot), you'll connect at a much slower speed, and you'll experience lost packets, but if you have a great connection the difference will not be noticeable over a wired connection.
I've been using wireless for gaming for over two years now, and have yet to experience any problems. My connections are very solid, no lag (not any more than when I used to have a direct connection to the modem)... 38ms to
http://www.flyaceshigh.com right now! I RARELY get disconnected, but then again my computer is less than 15 feet away from my router (separated by a wall), and I live out in BFE and the nearest house is about 2000 feet away.
If you live in a city area with power lines or an air port nearby and plan on using your computer 250 feet away from your router, then I'd say wireless is not for you.