Current local date and time:
http://php.net/manual/en/function.date.php
Note that since PHP 5.1 you have to set timezone for local time either in a format string or by calling date_default_timezone_set() function or by setting it in PHP ini.
http://php.net/manual/en/function.date-default-timezone-set.php
http://www.php.net/manual/en/datetime.configuration.php#ini.date.timezone
To store a date in mysql table you can use the mysql DATE type which I think stores date as a string but I prefer to store dates as Unix timestamp (not mysql timestamp which is different) but this depends on what you use the dates for. For storing Unix timestamp the mysql field tipe is integer.
http://dev.mysql.com/doc/refman/5.0/en/date-and-time-types.html