In Firefox, click on the search window's down arrow (top right). Choose Manage
Search Engines (bottom of list). Choose Get More Search Engines at bottom. Add
ISO hunt, Pirate Bay Search and Mycroft Project. Afterwards search Mycroft for
Torrent. You can add more torrent engines from there. There are well over 150
more torrent search engines. You can also search for engines for other things
that interest you.