SDK is provided with some good libraries for client and server parts. Win32, win64, Mac, linux x86, linux x86_64 and even freebsd (only server library is available for freebsd) seems to be supported by Teamspeak...
About the server part, there are few limitations if you don't own a license:
If no license key is present, the server will run with the following limitations:
• Only one server process per machine
• Only one virtual server per process
• Only 32 slots
In my point of view, this provides the availability to run one dedicated server (I mean a modified one embedding TeamSpeak support) for free and this is fairly enough for Smokin'Guns or ioQuake3 engine.
Btw as I'm definitively not easy with english language I'm really not sure about what we can do if we include TS3 server in the dedicated server. Maybe some else can take a look at the current available SDK archive: Go on the TeamSpeak site, get the "Client/Server SDK 3.0.0-beta1 (for integration with existing products/services)" download, then check LICENSING files and server.pdf documentation (containing the license agreement).
So I'm even not sure what to do with engine sources supporting TeamSpeak server.
Btw don't dream, TeamSpeak & Smokin'Guns won't be married unless we have enough time to look at it.