NetSky.V worm was discovered late night on April 14th, 2004.

Netsky.V does not send itself as an attachment but uses HTML emails which exploit vulnerability known as Microsoft Internet Explorer XML Page Object Type Validation Vulnerability (MS03-040) and tries to download and execute itself from an infected host.

and i found this interesting too

The binary code bears high resemblance to the latest NetSky variant, NetSky.U. Sharing up to approximately 86% of the code.

P.S.All taken from F-Secure.com