Probably have to go to the database to get it. The registration logs the time zone offset but you can figure out what timezone they are in from that ... An SQL query in phpmyadmin would look like:
Code:
SELECT `username`, `timezoneoffset` FROM `user` WHERE `timezoneoffset`='-12'
will get you all the users that have registered from Kwajelien timezone (mostly badboy spammers these days)
You could leave off the where clause and it would dump out all your members and the timezoneoffset they used to register.
You can get the actual time zones listing from
timeanddate
HTH