A more primitive alternative to using a python script for notification about new comments is to just use good ol’ AppleScript. Apparently, it can do XML-RPC calls and Growl notifications out-of-the-box (with Growl installed, at least). The script below will go out and check for new comments on your blog. It’ll only do it once as I didn’t want to dig into this too much, but maybe it’s also possible to sleep in AppleScript.
set BLOG_ID to 1
set USERNAME to ""
set MY_PASSWORD to ""
tell application "GrowlHelperApp"
set the allNotificationsList to {"Comments"}
set the enabledNotificationsList to {"Comments"}
register as application "WordPress Comment Notifier AS" all notifications allNotificationsList default notifications enabledNotificationsList icon of application "Script Editor"
end tell
tell application "http://localhost/wordpress/xmlrpc.php"
set comment_count to call xmlrpc {method name:"geek.getCommentModerationCount", parameters:{BLOG_ID, USERNAME, MY_PASSWORD}}
end tell
if comment_count is not "0" then
if comment_count is "1" then
set msg to comment_count & " new comment"
else
set msg to comment_count & " new commens"
end if
tell application "GrowlHelperApp"
notify with name "Comments" title "WordPress Comment Notifier" description msg application name "WordPress Comment Notifier AS"
end tell
end if