Date calculation

I have one more date based question. I have a month field ( $month ) and a day field ( $day ) being submitted by a form. I have a third field to be used as a date reminder for the information which was submitted as part of the form. It is a reminder to complete a task for the date was which was submitted as part of the form. How do I calculate the $reminder date based on $month and $day and have it output in the YYYY-MM-DD format? $reminder is the number of days before $month $day (I want to use $reminder in a date format to SELECT records from a mySQL table) This is why I am wanting put $reminder into a date format If $month was 6 and $day was 7 and $reminder was 6 then I would want the output to be 2007-06-01 --- We have already passed June 1st in 2006. However if $month was 11 then I would want the output to use this years date --- 2006-11-01 Any suggestions? Ron