• http://wwwneic.cr.usgs.gov/neis/plate_tectonics/rift_man.html - the USGS National Earthquake Information Center explains how they're connected.
• http://pubs.usgs.gov/publications/text/dynamic.html - complete text and figures from this book published by the U.S. Geological Survey.
• http://www.panga.cwu.edu/ - measurements of tectonic plate motion using GPS in the Pacific Northwest. Includes information about PANGA, the Pacific Northwest Geodetic Array collaborative project.

That is all the links for now. More will be added soon. Sorry for any inconvenience caused.