My new Vonage phone adapter arrived last night. It seems to be working fine, and it is mighty cheap. I love getting emailed notices of voicemail messages, and then listening to them online (which even works on my Linux worstation at work).
I'm a little disappointed at the adapter, though, which is actually a full sized Linksys broadband router. A significant selling point of the system is the portability of it, and this adapter is less than portable. It looks kind of funny having two of them on my tv (my own broadband router is a Linksys wireless router).