I personally don't currently take any mediation, but due to a family crisis I am learning all kinds of stuff about medication as I help my mother and father-in-law in their current circumstances.
I recently helped my father-in-law in organizing his current set of medications he takes. I was guided by my wife, who does take medication. Well after sorting out all his pills and getting them organized we had 5 bottles of medication to get rid of. I would like to get rid of these medications properly, rather than just throw them in the garbage where some person or animal could get a hold of them and harm themselves.
So what are the options out there?
I found two different options. One is to use the National Take Back Initiative. This program runs once a year in October. They have a site you can go to and enter your Zip code to find the closest drop off sites near you https://www.deadiversion.usdoj.gov/SEARCH-NTBI/ 
This year the collection day is Oct 26 2013.
So by the time you read this it will have passed.
Another method I found is at Walgreens. Walgreens has a Safe Medication Disposal Program, you can read more about it here http://www.walgreens.com/topic/sr/sr_safe_medication_disposal.jsp 
The long and short of it is you can go to your local Walgreens store and buy a TakeAway return system. I did just that this morning. Walgreens charged me $3.99 + tax for it.
Here is a front image of the box
Here is the back side.
The package contained one envelope with a pre-paid postage stamp on it and a set of instructions.
(I blacked out the USPS code in this image just in case)
Looking at the instructions there are a few types of drugs you can't put in here. They say no controlled prescription drugs. The short list of controlled drugs they give as an example are
In my case none the drugs I had to send in were "controlled" drugs, so I simple slipped them in pill bottle and all. In fact they want you to keep them in their pill bottles. There are some further instructions for liquids.
I easily put 5 pill bottles in this bag. I would guess it should hold about 10ish.
I sealed it up and took it to a local mail drop. I am in a condo and we don't have a place to put large packages going out so I had to drive by and put it in an old style mailbox.
Overall I like the kit, I wish it were free but $4 is not bad to have the ease of mind your pills are being disposed of properly.
 National Take Back Initiative Collection Site Search
 Safe Medication Disposal Program