If you are being sponsored by an employer, then he must employ you abiding the recruiting process of DOL (Department of Labor) standards. The employer must then file Form I 140 with the USCIS.
If you are being sponsored by your family member then the sponsorer must be a US citizen or a permanent card holder and should file Form I-130.
For more details visit the Immigration Article Apply for a Green Card @ http://www.immigrationdirect.com/immigration-articles/apply-for-green-card/index.html