To use Atomic with Blogspot you must first find your service.post URI by doing the following:

1. Go to your blog page on blogspot.
2. View the source of the page.
3. Look for a link in the header with a 'rel' value of 'service.post'.
4. The 'href' value of that link is your blog service.post URI.

To setup a service with Atomic, just click on the 'Add Service' toolbar button in the sidebar and then do the following:

1. Fill in the form as you normally would do.
2. Use the service.post URI as the introspection URL
3. Check the 'google' check box for google's client login
4. Check the 'fake introspection' check box.

That's it.