A new MSN "beta" is being offered to lure folks into infecting their existing PCs and MSN environment.  As a best practice, never accept software updates or products by email.  As an example, Microsoft does not distribute any software by email.

Virkel.F: Spoofed as an MSN Messenger beta 8 download

QUOTE: There is no MSN Messenger 8. Not yet anyway.However, there's a new virus going around pretending to be "MSN Messenger 8 Working BETA".  There's two ways to catch it. First, by downloading it from a fake site where it has been supposedly "leaked" ...