The broader SmartOS community has put together extensions to the SmartOS core to enable additional and different functionality. While encouraged, these are not supported by Joyent. If you have any issues with these, please contact the folks who maintain them.
EveryCity has made available an additional set of packages and repositories. For more information on using it and getting started, read the instructions.
Spice is like VNC, but with support for audio and better performance. Read on for more information on how to get started.
Heinz Gies has worked on web and remote management facilities for SmartOS. For more information on what you can do and what it offers, check it out.