Earlier today, on twitter, @skoop asked: "dear #lazyweb, when I use DateTimeZone('GMT'), why does format('e') output UTC?" [...] As you can see [the example with a format of "e" on a DateTimeZone('GMT')] has UTC and not GMT as you might expect.

Derick mentions that sometimes, systems require "GMT" instead of "UTC" in the output they're given. To work around this issue, he shows how to add a "type 2" timezone to the DateTime object by including it when you initialize the object (code samples included). Using alternative methods, you can add these "type 2" timezones in three ways - an offset in the initial string, using the abbreviation (like "EST" or "PST") and specifying the long version of the timezone (like "America/Montreal").

PHP comes with an extensive catalog of date and time functions, all designed to let you easily retrieve temporal information, massage it into a format you require, and either use it in a calculation or display it to the user. However, if you'd like to do something more complicated, things get much, much hairier

To make things easier, they enlist the service of the PEAR Date package to help bridge the gap between the time zones faster. They give some of the basics of using the package before actually getting into the time zone conversion. The code is pretty straight-forward and they even include other simple tips like how to calculate the GMT offset and how to add and subtract timespans.