Can someone please enlighten me? I am a green card holder and i filed the I-130 on behalf of my wife in march 2001 and apart from receiving a receipt, i haven't heard anything. Meanwhile i have been seeing people on the board who filed later and seems to have been called for interview.
How exactly does this work and i'm i at a disadvantage because all i have is a GC?

Those who got there interview already could be that they are married to a USC. The spouse of USC does not require immigrant visa number, while the spouse of GC holder does. From what I understand your wife is in F2a category. The priority date from visa Bulletin (http://travel.state.gov/visa_bulletin.html)
says June1997, if Mexican Jan1995, if Philippines June1997.

You can also the details of the law from INS.
http://www.ins.gov/graphics/howdoi/spouselive.htm