Many airlines are going to Electronic ZED fares. I have used them on Air France and KLM. It's great because you don't need a bunch of tickets before going to Europe and all booking/listing/payments can be done on a computer or iPad at the last minute. The fare is paid by credit card and if you don't use it, it takes just a couple days to get your CC credited. The flexibility is incredible now.
My airline has a link to the E-ZED through our travel page. Unfortunately you have to be an employee or retiree of our airline to get to the link. I think all airlines will eventually go this route.
I'll tell you if its between an ID90 or a ZED fare, ZED fares are much cheaper and the way to go 99.999% of the time. Just a tip. Not the tip. No homo.
As far as where to get them, most airlines have electronic agreements set up with some carriers you can buy thru a link on your travel site, or zed fares you can order from HQD and get in the mail also via the travel site.
I guess with ID'90 i'm showing my age lol....Yes, I agree ZED's are probably the better way to go. I am trying figure out where to get started since we don't have a travel department or ticket counter being a freight company...