Here is a quick way to set a timezone:

<php putenv(‘TZ=America/New_York’); >

A list of timezones for php: http://www.theprojects.org/dev/zone.txt

To get the timezones into a file quickly:

wget http://www.theprojects.org/dev/zone.txt

cat zone.txt | awk ‘{ print $3}’ » timezones.txt

Remove the first few lines and you have an easily read file that you can make a selection box out of.