Yup, I've had lots of emails like that. Apparently it can find out an email address that has sent something to you earlier and replicate that address.
Others have contacted me too, complaining that I sent them a virus, when in fact.. I sure as hell didn't; it just grabbed my name from their address book or email logs and made it look like I did.
Sponge.. you get about 20 a day? Damn.. thats pretty good. Yesterday, I believe was my spam record, about 660 spam emails in one day

(of course, they all went straight to my trash can becuase of a spam filter.. but impressive nonetheless.
