Problem with my Linksys router when gaming

My setup: WRT54G Linksys router with two computer connected wirelessly on a
WMP54G Linksys adapter which is connected to a Westell DSL modem. No new
wireless phones in the house (2.4Ghz or otherwise), and the router is only a
few rooms away horizontally from the wireless computer.

The problem: I only notice the problem when I game, since the connection
seems 'stable' otherwise. Anyway, in the middle of a pleasant Battlefield 2
experience, I get what I can only call "hiccups" in the connection, which
manifests itself in-game as a brief 1 - 2 seconds of 'lag' and the message,
"There is a problem with your connection." Just a second later, the game
picks back up and plays normally... until it happens again. I'd say this
occurs at least once a minute, making stressful battles even more frustrating
when a "hiccup" comes along and gets me killed. I usually get a ping
of ~100 when I play, give or take 50. Not too good I know.

To make a long story short, the WRT54G router and WMP54G adapter are brand-
new, with few security options enabled to ease troubleshooting. I'm not all
that keen on wireless options.

Can anyone help me with this problem or is wireless just bad for gaming?