Auchen, good note. Where a tire is available in multiple sizes, I have them listed together horizontally, by descending tire size.
rumrunn6: Your local bike shop or the internet. Amazon has most of them, Niagara Cycles, Biketiresdirect (never ordered from them but they showed up when searching for available sizes/weights). The Forte tires are just available at Performance Bike (online or in their stores). If anybody wants to note any particular online stores they've had good experiences with, we can add a list to the end of the post.
I don't know about adding an individual link to buy each tire/size though, since they may change often. Just googling for the brand + model + size should get you a lot of results. If you use the google shopping search it may even compare prices for you.