Most Linux boxes should be configured using UTC and the CMOS time and en entry in /etc/localtime. The only time this should not be done is when your are running a dual boot system. If your CMOS clock is set to localtime, and you don't want to set it to UTC, then you should either move the /etc/localtime file or set the timezone with /use/sbin/timeconfig.
# mv /etc/localtime /etc/localtime.bak
The prefered method of running a Linux server is with the timezone set to UTC. When running UTC, you will need to set the /etc/localtime file to the appropriate timezone. This can be done on some versions of Linux with the /usr/sbin/timeconfig command or it can be done manually by copying the timezone file from the shared directories.
# cp /etc/localtime /etc/localtime.bak # cp /usr/share/zoneinfo/America/Phoenix /etc/localtime