The kreg jig came up in another thread. Yes these can be quite useful in making your brackets. I just bought some furniture that was made using furniture grade plywood and a kreg type design. What they did was use some fairly skinny screws so that there was a lot of material remaining to screw through. If you look at the website,
http://www.kregtool.com/PocketHole-Screws-and-Plugs-Prodlist.html these are specially designed screws. If I were to use a kreg jig I would use their screws because it seems to maximize the amount of material you keep on the cut, plus a flat head for good holding power. If they have drill bits specifically limiting the size of the hole, I would consider those as well.
What I would not do is buy kreg jig then use some cheap old trumpet style screws from a local hardware place. I think you'll find the performance is poor because they will have a tendency to "mushroom" out of the jig hole. This does not make the join as tight and solid as it could be.
Another factor with the Kreg and mushrooming is to make sure you have your driver set with a tension clutch, that means when you drive it in, it only goes in with so much force then the clutch enables. This will help you from 1) chewing out screws and 2) mushrooming the material.
EDIT: Here is the smallest kit they sell, the "jr." allows you to drill both holes at once.
http://www.kregtool.com/Kreg-Jigreg-Jr-Prodview.htmlThe more I look at this the more I drool over it! You can see the drill bit is specialty and so is the bit for the square head screws. I don't think a regular 1-2 " square bit will go deep enough.