Thanks for the response, soulgrind, but the sticky notes aren't of any help. They all refer to a standalone WordPress installation. On WordPress.com, the XML-RPC and ATOM remote facilities are automatically enabled. What I don't know is how to fill in the End Point or Blog ID for a MetaWeblog implementation. Anyone else have any ideas?
I cannot add a Drupal blog. I receive the error message "Invalid API". I am able to post to Drupal via other remote facilities, such as Windows Live Writer, Word, etc. Anyone have any ideas?
Never mind... I found the answer from Zach Harkey in a sticky note on the instructions page. I'm copying them below for anyone else who encounters this problem.
Blog Type/Service: MetaWeblogAPI Enabled Blog Blog Id: Set this to a single content type (e.g., story) Your Blog URL: http://example.com Blog Name: example.com Endpoint: http://example.com/xmlrpc.php Be sure to enable the BlogAPI module and set proper permissions for the user account matching the Username and Password entered here.