For premium members of MegaUpload and RapidShare, this tool will make life easy. MuDownManager is an open source, free download manager that simplifies and accelerates downloads from RapidShare and MegaUpload. This program is also cross platform, and works with all versions of Windows. Linux and Mac OS X.

This tool is lightweight with an attractive GUI, and allows batch downloading of a list of URLs. It can also copy links from the browser directly and utilize them for downloading. It is also pluggable and other download sites’ support will come in future versions.
On launch, you need to provide the login info for your account. The download features are available only after that.

This tool requires you to have a premium MegaUpload or RapidShare account, and hence the download screenshot above has been taken from the developer’s website since we did not have a premium account available at the time of review.
MuDownManager is Java-based, and ran fine on our test machine running Windows 7 32-bit OS.
Download MuDownManager