Joshua pointed out that a new version of Syndirella is available. He also writes:
I haven't seen the source of Syndirella, I wonder how hard it would be to add plugins for different posting schemes (ie, DOTNETWEBLOG, Blogger, etc).
This is a great idea. Scott's extensions to Syndirella to allow a rich client blogging tool for DotNetWeblogs.com is great, but unfortunately it doesn't scale well, since you're essentially working off a copy of the code base.
If Syndirella exposed an object model, much like Outlook does, and provided a generic plug-in mechanism, Scott's tool would be isolated from changed to the Syndirella application.
I would think with .NET's reflection capabilities, this would be fairly trivial to implement too. You can simply allow assemblies to register with the application, and using a particular interface, connect and do what they have to do.
Maybe if I have time tonight I'll play with this. It would be neat. Making things extensible in this way always seems to make other people come up with interesting and new uses for a tool... :)