In article <42f186e.0209270825.663d5fe1 / posting.google.com>,
  martindemello / yahoo.com (Martin DeMello) writes:

> Analogous to Time#gmtime, but sets the time to zone z, where z is
> specified as GMT +/- some number of hours (or possibly using the
> standard "named" timezones). e.g.
> t = Time.now.atZone(+3) or t = Time.now.atZone("CST")

If you have to parse RFC2822 Date: field, time.rb may help you.
It is distributed with ruby since 1.6.7.

Note that there are several standard definitions of a timezone
abbreviation.  At least, CST is:

-06:00 in America/Chicago
-05:00 in America/Havana
+08:00 in Asia/Harbin
+09:30 in Australia/Darwin
+10:30 in Australia/Adelaide
-- 
Tanaka Akira