Hi,
Ed2k links are designed to be opened using a peer-to-peer (file sharing) program called eMule, which is allegedly one of the biggest and most reliable peer-to-peer file sharing clients around the world - but then they all say that.
From Wikipedia:
eMule is a free peer-to-peer file sharing application for Microsoft Windows. Started in May 2002 as an alternative to eDonkey2000, eMule now connects to both the eDonkey network and the Kad network. The distinguishing features of eMule are the direct exchange of sources between client nodes, fast recovery of corrupted downloads, and the use of a credit system to reward frequent uploaders. Furthermore, eMule transmits data in zlib-compressed form to save bandwidth.
For more information, or to download the program check the links below...
Hope this helps.