date maniplations

Hello, Sorry if I am confused by the date functions in the manual but I am. Here's what I want to do: I have a string in the form MM/DD/YYYY. I wish to: 1) convert it to a date 2) add $n days to it 3) convert back to a string in the same format above I believe I can accomplish [2] and [3] with: $mytdate = date("m/d/Y",mktime(0,0,0,date("m") ,date("d")+$n,date("Y"))); How do I accomplish step 1? Can I type cast a string to a date? Thanks, Don