Convert date as text to actual date

I've been sent a spreadsheet in which one column represents dates, but they have been entered as plain text, MM/DD/YYYY (ie 12/31/2008).

I ultimately need to import this as a CSV into a program that only understands dates in the format DD/MM/YYYY.

I'd ideally like excel to recognise this field as containing dates, but I can't figure out how to do that, or even how to swap the days and months around as text. I'm using 2007.

Any help appreciated