I got this same emal last night. I called the # 312 area code and a guy answered and said it was his girlfriend and she thought it would be funny if she sent a message to all of her friends in order fort hem to call him to "Jack him off" It was a real pesron who answered so beware! Its def a scam!
It's a scam and you shouldn't reply in any way. If you live in the NYC area, watch the 11pm news on WCBS (ch 2) on Monday 6/12/12. Consumer Reporter Asa Arons will have a report on the scam. I personally don't know what it's about since I don't have texting on my phone, but I'll upload the report on YouTube.