The iPhone is a capable little chap in its own right, but it also makes for a decent way to control another PC or Mac remotely.  As for how to do that, you've got two options: either a full remote setup using something like VNC, or function specific such as this uTorrent BitTorrent client interface specially fettled for the iPhone.

In its current form you can adjust the status and order of running torrents, pause and resume them, and add new torrents through either direct input of an URL or a Mininova ID.  David is working on new functionality, hopefully including direct search so that you can easily locate and add new sources.

Installation doesn't require a Jailbroken iPhone, as it's a web-based interface, but you will need to make some changes on your PC.

[via forum.utorrent.com]