I then received notification that I was reffered to another survey:
Thank you for your recent online application on Craigslist to join our Focus Groups. We appreciate your quick response as it reflects a good sense of responsibility and efficiency. The position you applied for is already occupied, but we have another survey that pays he same $350 Per survey. Only few candidates are required for this survey, so kindly go through the information below and get back to us if you are interested.
We are a result-oriented Development and Management Consulting firm involved in helping Companies to achieve market leadership and Improve connections between professional service firms and their client organization. Our company is currently conducting a survey on MoneyGram Outlets to help measure and improve the effectiveness of the services they provide.This is as a result of complaints from some reliable customers about their unprofessional approach to work in most Money Gram centers.
The survey involves you patronizing a MoneyGram Outlet in your area as a customer and give us a feedback on your overall customer experience by filling a simple online questionnaire. Each survey takes a maximum of 30 Minutes to complete and you'll be paid $350 for every survey completed, No Sales involved and this will not inconvenient your present job.
If you are interested to participate in this survey, please send us a reply with your information in the following order

No word until 2 Feb when I received notice I was accepted:
You have been Accepted as one of our Survey Agent in your neighborhood and the survey date is Feb 1st, 2011
You will be evaluating MoneyGram Outlets in your neighborhood as customer and give us feedback on your overall experience by filling out an online survey form. You'll be paid $350 for this survey and payment to cover all expenses for the survey will be delivered to you on the above date.
You'll be required to fill out a survey form after the survey using the below pointers:
1) How long it took you to get services.
2) Ambiance/Outlook of the Shop/Outlet
3) Customer service professionalism
4) Reaction of personnel under pressure
5) Information that you think would be helpful
6) Your comments and impressions.
Respond to this email on your acceptance to carry out the survey and confirm that your Full Name, and Mailing Address you provided to us are correct.
Thank you and hope to hear from you asap today.
Your faithfully,
David Provenzano
Research Coordinator
Groupnet.org I then received, today, notice that payment had been mailed:
How are you doing today? You are on our shortlist for MoneyGram focus group in your area.Your payment had been mailed out via USPS courier service and it will delivered to you within 4th - 8th Feb.Please let us know as soon as you get the payment,we will send you instructions for your MoneyGram survey as soon as payment delivered to you.
We want you to acknowledging this email ,if you will be available for the survey.You still going to get $350 for each survey you carried out.
Your prompt response to every email sent to you shows the ability of good survey agent.

Is this a scam? I think so. What should I do with the check when received?

Thank You