If you pay someone over $600 and they are not incorporated -- you need to provide them with a Form 1099 and provide a copy to the IRS. Also, if you pay any amount to an attorney you must provide them with a Form 1099. There are some exceptions, so consult with your accountant or attorney for special circumstances.
Disclaimer - This response does not constitute legal, accounting or other professional advice. Only through a personal, confidential consultation with qualified legal counsel can anyone properly evaluate their own unique legal challenges and determine what, if any, appropriate legal strategies and tactics should be implemented to meet those challenges.
Circular 230 Disclaimer - "Nothing in this response is intended or written to be used, and cannot be used by any person for the purpose of avoiding tax penalties regarding any transactions or matters addressed herein. You should always seek advice from independent tax advisors regarding the same.