You're right, it could be environmentally damaging to simply throw the stuff away. In addition, it's probably illegal.
I found a list of several dozen companies/organizations in my state by simply going to my State Web Site, and running a search for "computer recycling" (or something similar).
As an example (not knowing where you are), here are the links I went to/followed:
1. My state's official Web site:
http://www.colorado.gov/
2. Clicked on Search:
http://www.state.co.us:8765/
Entered: "Computer Recycling"
http://www.state.co.us:8765/query.html?col=schp&ht=0&qp=&qt=computer+recycling&qs=&qc=&pw=100%25&ws=0&la=&qm=0&st=1&nh=25&lk=1&rf=0&oq=&rq=0&si=0
That gave me a list of many possibilities, including:
Clicked on: OEMC - Electronic Recycling
Computer Recycling Collection Events Addressing the Disposal of Computers in Colorado Program Description The Challenge: Computers and electronic components are becoming obsolete at a rapidly increasing.
Hereis the list It took me to:
http://www.state.co.us/oemc/programs/electronic_options.pdf
REMOVE SPACES from the pasted URL.
I found a company that will pick the stuff up, and they will even PAY for some usable equipment. Worst case, they pickit up, pay nothing, charge nothing.
I'm sure your state may have a similar list on their Web site.