I have utorrent running on my home server (Vista Ultimate) 24hrs*7day a week and have a variety of methods for connecting to it.
1) Remote Desktop Connection - this microsoft client is available for Linux (Ubuntu 8.10 in my case), OS X (Leopard) and all sorts of Windows.
2) WebUI works from firefox (and I think IE7/8 too) on any platform
3) I also use utorrent mobile java program on my Nokia N82 to connect from anywhere via GPRS to manage bandwidth consumption (pause all, resume all) and specific torrents (pause, stop, resume, remove torrent (and data)).
To use it, create a bookmark with any name and fill its URL with the code from utorrent forums
You'll need to edit the code by changing
to your host and port (e.g. "mydomain.dyndns.org:8080"). If you don't want to login each time, you can even add your login information (e.g. "username:firstname.lastname@example.org:8080").
Now, whenever you are on a webpage containing some .torrent links, click your bookmark, then click the .torrent link that you want. It will automatically (in 4 seconds) direct you to your webui where you will see new .torrent added to your list.