Clarification
There has been quite a few "mis-information" posts!
If you applying through either traditional Labor Certification or Reduction in Recruitment (RIR), the Priority Date (PD) is the date when State Employment Security Agency (SESA) inputs your information into their database and assigns you a case number. They will send you a letter/notification that you have been assigned a case number with your priority date. SESA is supposed to check your labor certification application and only make sure everything is in order (this nominal task is taking them 7-8 months at some service centers!). After this they forward your application to the regional labor department called the Department of Labor (DOL). The DOL then enters your case into their database and assign you a receipt date (RD). It is here at DOL that the "real" work of adjudication of your labor certification takes place. The certifying officer (CO) looks through your paperwork and does one of the three: 1. Sends you a Notice of Finding (NOF) (meaning there is a significant discrepency in your case that needs to be addressed within a specified period of time) 2. Sends you a Request for evidence (RFE) (meaning the CO needs further evidence for some aspect of your case) or the best of all 3. Certifies your labor
Once your labor gets certified by DOL you can file for I-140 with one of the four INS service centers-Vermont, Nebraska, Texas, California-depending on the state where you currently reside.
After your I-140 is approved by INS service centers, it is valid for life (i.e. it is permanent). The next step is adjustment of status from a non-immigrant to an immigrant by filing I-485. Most people include the name of their spouses and minor childrens in their I-485 application if they haven\'t already.
This is the final step in this journey and unless there are severe problems (legal or medical) you will get a permanent resident visa on your passport. Remember you are still a citizen of your home country at this point in time.
Goodluck and godspeed!
-krsn