In our first-look review of Google Wave, we argued that - like Twitter - Wave needs applictions for it to be truly useful. The first of those desktop applications has arrived - albeit in a very limited state and only for Mac users.
Waveboard is currently in version 0.4, and is being called "simple and practical" by users who've tested it. All it does is put the web interface in its own Window, as if it was in your browser. It also puts out notifications when things happen via its dock symbol, menu entry and a growl notification. Not much for now, but still better than the web interface.
The same developer also has an iPhone version, which is featured in the brief video above. That's not quite out yet, but it's been submitted to the App Store for approval. When it's up and ready for download, we'll be sure to let you know.