I had a really good experience using the RPX module for Drupal 6, today. RPX is a service that lets your Website visitors login with one of their existing Open Social / OAuth services. RPX has a freemium pricing model.
Drupal 7 Installation Notes
Created a MySQL (i) database, (ii) db user and (iii) password for the user
Uploaded contents of the D7 Alpha to http directory
Selected "Standard" install
Saved and continued at language choice, English (built-in)
