there's no software to boost overall net speed but there's osme tricks for gaining the maximum speed provided by your ISP.
1. Use Opera Turbo Boost if you want quick page loading time.
2. While downloading torrents always download those which has more seeders and less peers.
3. For normal download ( if the server supports ) use Internet Download Manager.
There are no programs to boost internet speed. Although there are tons and tons of them on net yet they do nothing except eating your resources. Do what topgear said. Can't give you any better suggestions than what he just gave you.