This is the best website I found that pretty much summed it all up for me http://www.artandappetite.com/2009/11/ganache-instead-of-buttercream/
And this website did a great job of explaining it also http://sugarsweetcakesandtreats.com/2010/05/covering-a-cake-in-ganache.html
I use regular semi-sweet Hershey’s chocolate chips to make my ganache plus heavy whipping cream. And I use the 2:1 ratio (i.e, 12 ounces chocolate to 6 ounces heavy cream)
If you want to make white chocolate ganache you would have to do the 3:1 ratio (i.e, 12 ounces chocolate to 4 ounces heavy cream)
Hope this helps!
