How do I convert datetime to ISO 8601 in PHP

How do I convert my time from 2010-12-30 23:21:46 to ISO 8601 date format? (-_-;)

Object Oriented

This is the recommended way.

$datetime = new DateTime('2010-12-30 23:21:46');

echo $datetime->format(DateTime::ATOM); // Updated ISO8601

Procedural

For older versions of PHP, or if you are more comfortable with procedural code.

echo date(DATE_ISO8601, strtotime('2010-12-30 23:21:46'));

After PHP 5 you can use this: echo date("c"); form ISO 8601 formatted datetime.

http://ideone.com/nD7piL

Note for comments:

Regarding to this, both of these expressions are valid for timezone, for basic format: ±[hh]:[mm], ±[hh][mm], or ±[hh].

But note that, +0X:00 is correct, and +0X00 is incorrect for extended usage. So it's better to use date("c"). A similar discussion here.