How to recognize phishing email messages, links, or phone calls
http://www.microsoft.com/security/online-privacy/phishing-symptoms.aspx
My rule of thumb:
1} Do they tell me the name of the sweeps?
2}
Did I enter this sweeps?
3} Is the email address consistent with the sponsor/promo?
4} Is the prize I "won" listed as a prize if it
was a sweeps I entered?
If NO to any of the above, it's a scam.