There are quite a few decent automated downloaders supporting simultaneous downloads from various file-sharing services like RDesc and Tucan, but all new Java based multi-platform FreeRapid Downloader would be one of the best multi-service downloader we have ever came across, supporting fully automated downloads from 87 file-sharing services like Rapidshare, Megaupload, Mediafire and Hotfile to name a few.
The utility supports plugin based architecture allowing easy expansion of supported file-hosters and comes equipped with features like support for proxy lists, download history, smart clipboard monitoring, simple CAPTCHA recognition, automated plugin updates, multi-language support and interface skins.