http://www.php.net/manual/en/function.getdate.php
getdate does that for you, read the link above, there are parameters you use to get the certain day, month, year, etc...like...
$today = getdate();
$month = $today['mon'];
$day = $today['mday'];
etc...
here are the rest from www.php.net
Table 1. The following characters are recognized in the format parameter string
Key Description Example returned values
"seconds" Numeric representation of seconds 0 to 59
"minutes" Numeric representation of minutes 0 to 59
"hours" Numeric representation of hours 0 to 23
"mday" Numeric representation of the day of the month 1 to 31
"wday" Numeric representation of the day of the week 0 (for Sunday) through 6 (for Saturday)
"mon" Numeric representation of a month 1 through 12
"year" A full numeric representation of a year, 4 digits Examples: 1999 or 2003
"yday" Numeric representation of the day of the year 0 through 366
"weekday" A full textual representation of the day of the week Sunday through Saturday
"month" A full textual representation of a month, such as January or March January> through December