The message was: congratulations, your number made you Walmart's winner of the day, goto http://www.walmart.com.wonacontest.com to claim your prize! you have 24 hours to claim.

I got the same message on my cell phone that Nathalie got.  If you go to the site as mentioned in her comments it takes you to a site that has nothing to do with Walmart.

I received same message. I think is a scam.