It's also worthwhile to note that while creating m1-large instances in [our] us-east-1a zone, we've been hitting insufficient resources exceptions when attempting to bring up instances. Now's an excellent time to apportion for mission-critical instances which come up and down with regularity, it seems like.
Which seems a bit easier, even to a command-line junkie like me.
There's no way to do this from the console at present. It can be done from the command line or via the APIs.
I haven't tried it yet, but it looks like it'll automatically 'convert' your existing instances into reserved? IE, I don't need to start new instances to take advantage?
I've heard the same, though I'm not sure if they retroactively apply it to a long-running instance, prorate the rest of the billing period at that rate, or simply convert to the new pricing scheme for the next billing period.