Caren, I spent the better part of two hours 2 weeks ago doing the same thing! I came up with plenty of sites showing me how to candle infertile eggs for 4-H competion. They showed 'blood spots, double yolkers, and meat spots', but very little success on fertile egg development.
What I do know, is that you'll see development of 'spider web looking' veins when you candle at about 3 days out from laying. If the egg is clear, it is infertile.
Good luck,
Carla

Ohio State University has a pretty good info site here, with clickable links to photos:

http://ohioline.osu.edu/b633/index.html

More good info here, with drawings and descriptions of daily development, with links to more info at the bottom of the page:

http://www.urbanext.uiuc.edu/eggs/res27-timing.html

UC Davis has more info and good pics here:

http://animalscience.ucdavis.edu/Avian/pfs32.htm

Even MORE info here, no pics but tons of reading:

http://edis.ifas.ufl.edu/BODY_AA204

Happy reading, hope this helps! :)

Velvet

I also spent ages last year looking for good photos so I could compare it with what I saw. What I discovered was that I couldn't actually see all that much (maybe my technique was not great), however, what I saw for my fertile eggs is exactly what you describe: "I was able to figure out the air pocket but the rest was dark."

Now, after doing several clutches more since then, if I see what you have seen, I know I'm going to be getting some chicks.

Good luck, and enjoy.

If you will candle them about the 7th day or after that a few days you can see pretty good because they are developing pretty good then. But this is duck eggs so it may be sooner for chicks because my mallards take 28 days to hatch and I know its sooner for chicks. Will go to my favorites and list a few sites I have about candling on them.....

http://www.urbanext.uiuc.edu/eggs/res26-candling.html

http://shilala.homestead.com/candling.html (this is a good one with pics and I think it's chicks)

http://www.david.crocker2.btinternet.co.uk/sheldon_pages/candling.htm (LOVVVVVVVVVVVVVVE THIS SITE AND HER STORIES! LOL)

http://lancaster.unl.edu/4h/Embryology/Candling4_8.htm

http://msucares.com/pubs/publications/p1182.htm

http://www.poultryconnection.com/quackers/mycandlepix/candle.html

http://www.msstate.edu/dept/poultry/avianemb.htm

Maybe one of these will help!
Rose

Here is a link that might be useful: GOOD ONE Shows embryo inside egg at different stages