Try this website. http://www.wunderground.com/

Put in the zip code and then on the left side of the screen you will see a box with current conditions. There will also be link in that box toward the bottom of the box that says "Weather History for This Location". Press this and you will be able to search by date. The search results include a graphical plot of the barometeric pressure. It appears that the results provided by zip code are set to find the nearest airport AWOS.