How to find international bus terminals?

[Tigre]

I have been searching online as to where to buy tickets from South American international bus lines. The couple of websites I found are either defunct or not offering sales online.

So when I get to Quito, how do I go about finding where the international bus terminal is where I can purchase tickets? Should I just hop in a taxi and ask the driver? If so, what's the particular Spanish phrase I would use? Is there any other way?

Plan is to fly into Quito, visit a few days, onto Lima for a few days, onto Santiago, then B.A. then back to Quito.

[Aqualung]

Try this.

http://www.ecuadorexplorer.com/html/buses.html

or this

http://www.goecuador.com/traveler-guide/land-international-transport.html#international

[BundaLover]

Just check out the standard guide books like "fodors","lets go" etc. You may be able to get the info online.