Here are the rotation parameters calculated from McQuarrie and Wernicke's (2005) reconstructions: Rotation Parameters: Western US Terranes to North America.
Original post that discusses their article (with link) and derivations: Google Earth: Restoration Parameters and Restoring Data Points.
Update (11/18/2008): The original spreadsheet (first link above) was produced from an obsolete program and consisted of erroneous results. The posted spreadsheet has been corrected. (Thanks to David Rowley for questioning the original values.)