Yazsoft has announced the availability of Speed Download 4.1.13, its latest update to the the fourth generation of the company’s award-winning download manager for Mac OS X. Version 4.1.13 includes various key improvements, optimized for Mac OS X 10.4.10 and a recommended update for all Speed Download 4 customers. As an added bonus, Speed Download now includes a link to the Transmission Bittorrent application. Transmission is a free, lightweight BitTorrent client featuring a simple, intuitive interface on top of an efficient, cross-platform back-end. Speed Download requires Mac OS X 10.4.6 or later, priced at US$25.