Here is an easy and effective mod to make your Weber kettle into a smoker-don't even bother with that Smokenator nonsense. It'll cost you about three bucks or so. Go to a masonry supply (Marvel has a few Valley locations) and get two fire bricks. You could use regular bricks I guess but I've heard they can explode, and I'd rather be safe than sorry.
Section off a part of the lower charcoal grate with the bricks. I make sure there's enough room on the other side of the bricks for a 1/2 size foil pan (for adding water and/or catching the drips). Load up charcoal and wood chunks on the small side of the bricks leaving room to use a mini-minion type method. I've cooked many different things and I've gotten upwards of six hours (I've not tried for longer) without adding fuel or really even messing around with it too much. There's just a small learning curve to know how to control your dampers.
Here's a pic, hopefully you get the idea: