Right now the landscape is split between startups providing the service and jquery/bootstrap plugins.
The startup offerings don't work for us since we're inside of Gmail which presents a unique technical challenge in regards to loading javascript, etc.
The libraries have the issue of things being "hard coded" meaning it becomes too difficult and annoying to make lots of tour variations, or do A/B testing.
Here's one that uses Selenium for recording the tour steps with Drupal used for managing the tour content (the site being 'toured' doesn't have to be running Drupal). http://walkthrough.it/
Configuration file with sections/selectors of the feature to highlight [1].
Model to determine if the user has unseen "tutorials" [2].
JavaScript to show an indicator that new features exist [3][4].
It looks like this, http://imgur.com/a/ZWaHV
[1] https://github.com/photo/frontend/blob/development/src/html/...
[2] https://github.com/photo/frontend/blob/development/src/libra...
[3] https://github.com/photo/frontend/blob/development/src/html/...
[4] https://github.com/usablica/intro.js