iTransmission is a native BitTorrent client for jailbroken iPhones, iPods, and iPads that uses libtransmission as its backend. Currently it supports:
-Adding torrents from either URL or magnet URL.
-Transmission’s web interface.
-Automatic port mapping (UPnP) for users behind routers.
-Choosing which network interface (Cellular network or WiFi) to use.
-Connection and speed limits
Files downloaded from torrents can be viewed from iFile.
iTransmission is available for download as an IPA (iPhone app) file. To install IPA files, you must have Appsync or Installous installed on your iPhone, available in Cydia by adding the source http://cydia.hackulo.us . To add a source to Cydia, open Cydia and go to Manage->Sources->Edit->Add.