AutoZone, quick lubes, etc. will take the old coolant.
It can be mixed with used oil for recycling.
There is no drain on the radiator, if you are replacing the bottom hose you can drill a hole in it.
If you ever have your radiator rebuild you can have them add a petcock.

 

My local AZ wouldn't let me dump my coolant in with the oil.

 

In the future you might want to obtain a primer bulb type siphon setup. I usually drain the reservoir with it first, then remove the bleed plug on the top of the radiator and push the hose all the way to the bottom of the side tank to siphon out as much as possible. You'll still lose a couple ounces of coolant when you pull the lower hose off the radiator, but nothing like the epic gyser when trying to drain the system by pulling the lower hose off.

 

I'll keep these tricks in mind when I have to drain it again someday.

My local O'Reily's only takes hydraulic fluids (oil, ps, atf, etc.), but there are other places nearby that will probably take it. I might actually be able to take it to a local transfer station that accepts some chemicals like paint and such.

I have it in a sealed bucket for now.

 

I used to work at Safety-Kleen, they do all of the used oil recycling for AutoZone, you can pour the coolant in with the waste oil.
If you mix it in a jug half and half with used motor oil they will never know the difference.
Just make sure it is mixed well before you hand it over to the guy.
In other words, shake the jug as you carry it from the parking lot to the store.

 

Yup. Always remember. Shaken, not stirred.

 

I just found out the local transfer station for the disposal company here takes antifreeze!

Now I don't have to walk into O'Reilly's all suspicious and shaky like Spike suggested. Whew!