Ian,
The SliMP3 and Squeezebox are implemented as a 2-piece system. The first being the hardware player that connects to your HT/Stereo and to your PC via Ethernet. The second being the server software that runs on your PC.
As such, the hardware player cannot directly access network-attached-storage, but must connect to it's own server software running on your PC.
As a hardware engineer, I really like this approach, since all of the "intelligence" of the system is contained in the server software and the hardware player is actually a pretty "dumb" device. This makes for easy upgrades and feature adds in the future.
As for the wireless aspect, it should work just fine on the Squeezebox, I'm speculating here since I haven't seen one in action. But, I actually have my SliMP3 connected into my network via an 802.11b wireless bridge and it
works just fine.
My understanding is that you can stream Internet-based music from the PC server to the hardware player, but this isn't something I've played around with. I believe it entails creating a psuedo-playlist that contains the URL and port number of the stream you want to connect to, then on the player you select that psuedo-playlist.
Dan W.