ifconfig vr0 -txcsum
This fixed it for me too!
What hardware are you using? ALIX? It would help to know the wireless driver and ethernet driver you are using. For me, it's ath0 and vr0.
It's an alix2c3. bridge0 contains vr0 and ath0, just like yours.
The problem for me was that whenever I did a cold or warm reboot of the alix, wireless clients would get an IP, they could communicate with other hosts on either LAN or WLAN, but not with the alix box itself (which also meant no internet access). I solved this by going into the options of the wireless interface and pressing save after each reboot, and it would all work again.
Now I have tried with 2 reboots, and running 'ifconfig vr0 -txcsum' have had the same effect as pressing save in interface options, it all worked like a charm again!
I'm currently running pfSense-1.2.3-512mb-20090917-0347-nanobsd, but this problem has been around for quite some time for me.