In official doc and forum could not find fresh info. Have anyone succeeded to install transmission on OpenELEC 2?
There are 2 different transmission addons for XBMC:
To get them on OpenELEC 3.0:
Server Add-on - System → Setting → Add-ons → Get Add-ons → All Add-ons → Services → transmission
Client Add-on - Programs → Get More → Transmission
Instead of using the client Add-on you can use the web-interface by browsing to http://[openelecIP]:9091
from any computer on the same network.
To find out the IP of your XBMC navigate to System → System Info → Network