Wireless router traffic monitor

I have few neighbors around me and far to few of them could probably even power a computer on, much the less use one. I usually always set the mac filter to only allow connections from mac addresses I list/add. I purchased a new router and forgot to enable mac filtering and today I found that someone has/had connected to that wireless router from a computer/wireless device I do not own.

I was wondering if anyone knows of a decent and/or free traffic monitor that can pull log data from wireless router(the one I am referring to is Linksys WRT54G v.8) and tag IPs, maybe computer names and MAC addresses as well. Thank you.

Obviously not as much fun as watching someone.

Use the free aplication Wireshark, you will find it very usefull...