6pm Eastern time would be 5pm Central time. Central time is exactly one hour behind Eastern time, so whatever time it is in the Eastern time zone just subtract one hour, and there you would have your answer for the time in Central time zone.

For Mountain time subtract 2 from Eastern time.
For Pacific time subtract 3 from Eastern.
For Alaska subtract 4.
For Hawaii subtract 5.

For Atlantic time zone add 1 from Eastern time.
For Greenland time add 2.

source: http://answers.yahoo.com/question/in...1021844AAT0nYM

Took me about 15 seconds to google it, l2g.