I agree with probyte2u, there is still potential in this avenue for making money. I do think you need to have enough photos to really flood out the market. I also think you need to perform some research on the kinds of photos people are purchasing and downloading most. You can probably find this out by researching some of the more popular stock photo portals.
A few other things to consider. You probably need to have some of the best quality equipment out there so that your photos are high quality enough for people to want to purchase. You also need to make sure you can offer files that are as large as allowed.
And don't forget, if you're moving toward this industry there are also other options you can explore. You can provide photography for greeting cards and products (think Zazzle or Cafepress) or sell prints through portals like Smug Mug or Deviant Art. Take some time to explore all of your options. I think you could probably do a few of these and make some nice side income.