'redirecting' google

old pages still indexed

[humpingdan]

we've recently re-designed our site, and google has deep cralwed it - every single page, but google still displays old pages and descriptions,

how can i use this to my advantage, obviously we dont want multiple pages coming up for our keywords, and ive noticed from others sites i run that google will often revert back to old results unexpectedly!

should i setup redirects or something else?

Dan