Clutch: control Transmission torrents via the web
Clutch runs in your menubar on whatever port you choose in the settings (this port will need to be opened on your router/firewall of course). You can enable authentication so some wayward soul can't stop your download of "So You Think You Can Dance?" When you visit your Clutch URL (in the form of http://your-ip-address:port), you'll see a familiar interface that looks identical to the Transmission GUI.
Clutch lets you upload torrents remotely to your Mac, and you get most of the same functionality of Transmission via the web browser (stop torrents, pause torrents, view the inspector, etc.). It also supports SSL.