A BitTorrent client is a software that manages downloads and uploads using the BitTorrent protocol.

μTorrent – uTorrent is a freeware closed sourceBitTorrent avaialbe for Windows and Mac. This program is very small in size and use minimal resources. It runs on almost all new or old hardware and OSs.
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Vuze - Vuze (formerly knows as Azureus) is free BitTorrent client written in java relased in GNU GPL. Beside torrent is also allows used to view, publish and share DVD, HD videos.
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BitTorrent - This was first client that used BitTorrent protocol. Since version 6.0, this is rebranded version of uTorrent,it is no more open source software and available for Windows and Mac only.
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BitComet - BitComet is BitTorrent, HTTP and FTP client written in C++ for Microsoft Windows and available in 52 different languages. This software includes Flash Player to play video that can also be downloaded as standalone.
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Transmission - This is dual licensed free software under GNU GPL and MIT license. Transmission features simple interface, available for Linux, Mac OS X.
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