I read this in a magazine years ago. It's quite easy and you DON'T have to use the special no-boil lasagne noodles that they sell.
Basically, you want to make sure you have at least four cups of sauce and that the sauce is hot. Assemble the lasagne as you normally do (don't boil the noddles first, though). Start with one cup of heated sauce on the bottom of the pan, assemble the lasagne like normal, and end with at least one cup of heated sauce.
Next, you oil (very lightly) a large enough piece of tinfoil to cover the pan. You want to make sure that it is sealed tightly around all the edges, but tent it up slightly in the middle to allow for steam.
Bake the lasagne at the temperature called for in your recipe. It will probably take longer to bake than regular lasagne. Mine always takes at least 45 minutes to an hour. You can test it but be sure to reseal the foil tightly if it needs to bake longer.
This method sure beats the old way of boiling the noodles and trying to prevent them sticking or tearing as you work with them, and it does NOT require purchasing special, more expensive noodles. It is much easier and in my opinion, tastes a little better.