I posted a simple solution a while back, but evertime I try and search the archives it times out so I can't give you a link. It wasn't a mod though since the collecting and storing of the users zone was up to you. I only gave the code for adjusting the displayed time which is trivial.<

In Image's forum there is a timezone feature, so the mod for that must be floating around somewhere.<

Store the users time zone in the strM_TIMEZONE variable. Set the "Time Adjustment" setting in the admin panel to the inverse of your time zone to bring the server to GMT. Add the code below to the chkDate function in inc_func_common.asp.
The hardest part is modifying the profile pages to store the users time zone.
if fDate <> "" and strM_TIMEZONE <> "" Then
fDate = DateToStr(DateAdd("h", strM_TIMEZONE, strToDate(fDate)))
End if<

Mark, after seeing the earlier thread on this, I Used Garys suggestions and got this working. I used Invision Board(log-in - demo, demo) as a model, in fact the select box I use is Invision Boards .
As Gary said the server/forum time is set to GMT (I did play around with this and found it to be best). Then members adjust time in thier profile, there is an adjustment for DST.
I never released it as a mod because I wasn't to sure of it. But it has passed all my testing so far.
If your interested in testing it I will get the code together.
<

Yep, Aussie DST works a few weeks diff to USA DST, NZ DST changes are different again, then some timezones do not have DST at all ..... just remind the users to do the old +/- 1 when they need to.<