convert a current date into a future date

[Nicolas Cueto]

Hello All,

I'm looking for a ready-made script/formula for
converting a current date into a future date.
Of course, it'd need to take into account the
number of days in a month, a change in year,
and leap years. Centenial or millenial changes
can be ignored.

Something that, for example, would convert
the english date "12/29/09" to "1/5/10", or
"2/22/12" to "2/29/12".

Trying to save time having to do it myself.

Thanks.

--
Nicolas Cueto