All –
I am running WP 2.3 and XML Sitemap Generator for WordPress 3.0.2.1. I was having an issue wherein Yahoo was not being successfully notified (‘invalid appid’ error was being returned by Yahoo). I tried removing the ‘.’ in front of my Yahoo appid, and that did the trick.
Anyway, hopefully that helps if anyone else is having the same issue! For the record, I am just using a generic Yahoo application ID…