Rapget is a sweat little freeware program that can be used to download multiple files at once from over 60 file hosts including Rapidshare.com, Megaupload.com, Yourfilehost.com and others. The real beauty of Rapget lies in the fact that it automatically bypasses the annoying captcha that is used on most websites to prevent access with download managers.
It is furthermore possible to add username and password of premium accounts if available which has to be done for several services unfortunately. I was not able to download files from rapidshare.com for instance without adding premium account details.