Leech is a free download manager that runs natively on both Intel- and PowerPC-based Macs and requires Mac OS X 10.5 or later. It can capture all downloads from Safari, Camino, OmniWeb, and Firefox (via FlashGot) while staying almost invisible. Just click those download links and use that context menu like you usually do, and Leech will kick in automatically. Leech's rules let you define individual download folders and postprocessing applications for any given file type/host combination.

Leech