I have seen Sterno used for fire starting, but mostly for keeping the fondue, well, fondue like. I don't think they are of much use as a stove for significant cooking or water boiling. The cans I have bought also tend to leak <img src="/forums/images/graemlins/grin.gif" alt="" />
While not optimal, sterno will boil water. I use to carry stero as my only source (other than raw fire) for cooking. If you do use it you need a good windscreen and a pot that sits on top of the screen. I used a large peach can that fit around the sterno.
The setup was heavy (relatively) and took ~8 minutes to boil a cup of water, if I remember correctly. I moved on to using a Jetboil and have never looked back.
There are a hundreds of better options but it works. Like Pika said, Esbit is a better option.