I've been using phpbb for a long time now and i always came across the same problem every six months! yes, the timezones are all wrong. anyway, after a while, i figured it out, change the timezone by the admin panel AND my profile and everything is ok!
now, on a new install of phpbb, changing the timezone seems to make no difference. i've tried changing the board's timezone and the one in my profile. i've tried changing them to two different settings as well as the same, but nothing. I always see the GMT timezone.
a lot of members have commented on this and I have no idea how to fix this.
I've installed the 'today/yesterday' mod, so that the times are a little more user friendly, but the problem occured before I ever even dreamt of putting a few useful mods in.
you can see the timezone problem here: http://www.beunequaled.com/forum
it's an active forum, but feel free to register and have a look and tell me if you see different to what i've said. i hope someone else has had this problem but has found a fix!