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Probably the simplest way to find the rates is to fill in the particulars in this calculator, which is good to bookmark/favorite:
http://postcalc.usps.gov/
(I guess you would have to do it on January 27th or later to get the new rates. One hint: select "packages" even if you plan to ship Priority Mail; the "packages" will give you all the ways to ship a package including Priority Mail.)

I couldn't find comprehensive new postal charts (like Price List Notice 123), though I didn't try too hard. I believe those charts will come out on Jan 27th.)

Some links:

Highlights of the price changes:
http://support.pb.com/ekip/index?page=content&id=fa2341

http://about.usps.com/news/national-releases/2012/pr12_114.htm

https://www.usps.com/new-prices.htm

Robert