Strangely, the default page orientation in all my apps seems to be landscape view. For most apps from which I print regularly, this is no problem as once I've changed the orientation it seems to stick. However, when printing from Preview, a new app, or an app that I don't use often, this quickly becomes irritating. System Preferences enables you to change the default page size, but not the page orientation.
To change the default page orientation for all apps, open the com.apple.print.PrintingPrefs.plist file located in ~/Library » Preferences. I have the Xcode Developer Tools installed, so the plist automatically opens in Property List Editor, which makes editing easy. However, it is also possible to use a plain text editor and change the "integer" value of the key identified below. The key you want to change is:
Root
com.apple.print.PageFormat.PMOrientation
com.apple.print.ticket.itemArray
0
com.apple.print.PageFormat.PMOrientation
For portrait, the value of this key should be 1, for landscape it should be 2, and I assume that for flipped landscape it should be 3, though I haven't tried it out.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20070613051850612