So for lots of people who are hiking sheltered trails like the AT, much of which runs through forest, they're obviously proving to be a good solution. And yes, you can make one from a soda can. All you need is a cup to hold some alcohol, some kind of structure to hold the pot, and a windscreen made from aluminum foil. No pressurizing or anything required; you simply dump the alcohol in your makeshift stove, light the fuel, and cook. For a single hiker or heating small quantities of water for soup, coffee, or meals needing re-hydration, they're fine in many cases. For groups, boiling water to sanitize it, or melting snow in any quantity, forget about it.
You can find plans on the web for fabricating your alcohol stovejust do a Google search for "make alcohol stove." Of course, you also can purchase ready-made ones. The Trangia Mini is a popular model that sells for about $30 with a small cookpot (www.rei.com). Good luck!