|My cilantro, flowering|
Cilantro or Coriander: same thing. Cilantro is more often the leaves, coriander the the seeds, but they are the same plant.
In temperate climates, it's easy to grow, and it reseeds without much help from us. For those in climates with harsher winters, I believe you have to reseed it with a little more foresight and gathering of seeds.
The Tropical permaculture site has a great section on growing cilantro, whether for the leaves or for the seeds. Everything I've ever learned about it, plus some things I never knew, are mentioned on this site, so I would definitely recommend it!
Eating: It's all edible. You can eat the leaves, seeds, stalks, and even the roots! I believe the flowers are edible as well, but I typically leave them to make me the seeds I love to have!
Taste: uh...like cilantro? Yeah, I'm crap at descriptions.
With the leaves, some people seem to get a bad flavor out of this that others do not, somewhat like soap. If that's you, don't eat it, right? For the rest of us, it's a sharp taste, almost a little like a zingy pine taste without the pine smell. Seriously, it's a bit hard to describe. Adds a zesty, fresh feel...like minty freshness without the mint. So, yeah, I can't tell you what it is, just what it isn't. Try it and see!
With the seeds, it's a completely different flavor. The fragrance is very floral and sweet when the seeds are ground up.
The leaves are always added at the end of cooking or even after a dish has been removed from the heat, in my experience. Or raw. I believe the cooking destroys the flavor significantly. Stems and roots are more often added earlier in the cooking, so they stand up better. Seeds are also added earlier in the dish like you would with other spices.
Asian, Indian, and Mexican recipes often use cilantro and/or coriander. I've used raw cilantro in guacamole and salsa. I've added the leaves to potato, tomato, beef, chicken, fish, corn, chile, and cauliflower dishes (I'll have to put up my cilantro cod recipe sometime). I've chopped up the stalks and used them in stir-fries and when making Indian curries. I understand the roots can be used the same way, and that both can be used in making soup and soup stocks, especially for Asian dishes.
Helping with cooking.com gives the following information:
Coriander is predominantly used to flavour curries and soups but can be used in many more types of dishes and meals. Below are a number of ideas:
Use in all types of curries, pickles, chutneys and sauces.
Sprinkle over fresh salads.
Use to flavour soups, carrot and coriander is quite popular.
Use to flavour homemade bread, waffles and scones.
Coriander is used as an ingredient for some cakes and biscuits including gingerbread.
Use to add flavour to creamed cheese or mayonnaise.
Use to garnish meat, fish or vegetable dishes.
Use in meatballs, meat or vegetable burgers and other homemade dishes.
Add to stocks and gravies.
Use in marinades, particularly for meat and fish.
Coriander goes very well with mushrooms.
Use to spice up stir-fries and bland vegetables such as spinach.
So there you have it, some information about cilantro to help you along in your cooking. I'm sure I'll have more to add along the way.