Easiest way to control a remote bitcoind instance?
Assuming you're using a Linux-based system, Xpra is a great tool for running GUI apps headless and attaching to them on a remote system. Make sure you install a recent version from one of the Winswitch repositories.

I haven't tried the Winswitch front-end since command line usage is so simple. Just do this on your server:

xpra start :7
DISPLAY=:7 bitcoin-qt


And this on the client:

xpra attach ssh:my.server.ip:7