Although I'm not someone who regularly grows from seed, I stumbled across this site and found it very interesting. It is a site by a gardener who photographs seed pods, seeds, and seedlings to many plant varieties. There are also pictures of weeds in seedling form, for those of us who don't always know if what's popped up in the soil is a weed, or something they have planted. If you are wanting to pinch out seed pods to petunias but are not sure where it is because the flower has already fallen, you can see what the seed pod looks like. If you want to collect seeds from something for the first time, the photos are useful. Information about whether or not to nick the seed is also included and most helpful.
I did plant Snapdragon seeds in a flat outside, and I learned that it's time to take off the clear lid. Mine don't look as happy as those photographed-oh oh! I might try to collect some seed from my blue salvia this year.