$timestamp = strtotime("13-10-2013 15:00");
This can be important:
Dates in the m/d/y or d-m-y formats are disambiguated by looking at
the separator between the various components: if the separator is a
slash (/), then the American m/d/y is assumed; whereas if the
separator is a dash (-) or a dot (.), then the European d-m-y format
is assumed.
To avoid potential ambiguity, it's best to use ISO 8601 (YYYY-MM-DD)
dates or DateTime::createFromFormat() when possible.
http://uk3.php.net/strtotime