The nice thing about this project is you can build it to your exact specifications. We have a fairly small dining room, so I went with 36 1/2"x60" and 30 inches tall. You can go longer, shorter, wider, whatever you want. So the first thing you have to do is decide how you want this built. Decide the size, shape, finish, and type of wood before you start.
I built mine out of aspen because it's cheap, easy to work with, and fairly cheap. You COULD build the entire table out of construction grade pine for around $50, furniture grade lumber will run about $120 and up depending on what kind of wood you choose. It's whatever you want to do. Just keep one thing in mind, pine is very soft wood. Writing on the table, dropping things on it, etc. will dent and scratch it fairly easily. If you're OK with this and you like the knots, go for it. Some woods won't take stain as well as others, some are harder to sand and work with, and you may think some wood is just plain ugly. Do your research.
UPDATE: I built a matching console table for the dining room. Find it here: http://www.instructables.com/id/Build-a-dining-room-console-table-side-or-serving/
Step 1: Make the legs
My legs final length are 29 1/4" long. I start by cutting 4 1"x4" boards to 36" long FOR EACH LEG! You will have 16 3' long boards total when you're done. Now, you'll take 4 of them, lay them out and glue them together using wood glue. Don't be shy with the glue, if you don't have glue splooge out when you clamp it, you aren't using enough. You'll have four 3 1/2"x3" table legs when you're done. We will cut these to their final size once the glue is dry.
Step 2: Build the table top
Cut the 1"x6" and two 1"x8" to 45 1/2" long. Take the other two 1"x8" and cut them 36 1/2" long. We will be using pocket holes to butt them together. You'll need a pocket hole jig to put this together. I put 2 pocket holes every 10" across the boards, alternating sides of the board. Once you get everything drilled, run glue across the edge and screw everything together.
NOTE: Take care to make sure everything is as even as possible. The table top is what will be seen, and the more care you take to keep everything even now the happier you'll be when you get to the sanding and finishing stages.
Step 3: Cut legs to length
Now cut about 1" off one end of the board with a miter saw. This will smooth off the bottom of the leg. Measure up 29 1/4" make a cut, and you have your finished leg- 3"x3"x29 1/4".
Step 5: Lay out and cut aprons
I measured in 2" and set up my legs. I then measured the distance between the legs and cut my aprons. (should be 26 1/2" and 50") but measure to make sure, anything could throw you off a quarter of an inch, and if it's not perfect it will stick out like a sore thumb.
Cut the aprons. You'll notice that I glued an el cheapo pine 2x4 to the back of my pretty 1x4. It won't be seen, adds strength, and saved me some cash. I glued the pretty 1"x4" to the 2"x4". Put the pretty side out.
Now drill more pocket holes and screw them into place. This is what will hold the table together, so don't be shy with the screws.
I also cut another 2"x4" and screwed it into place across the center of the table. This will add strength and help keep the table from sagging a few years down the road.
Step 6: Sand
Now is when you get to summon your inner interior decorater. The distressed look is popular right now. This involves chipping, gouging, denting, and otherwise maiming your beautiful project. (I didn't do this). You may also choose to use wood filler to fill in any small gaps. (I did do this). If you choose to use filler and are staining the table you have 2 choices. You can get a stainable filler and put it on BEFORE you finish your wood, or you can choose a filler dyed to match the stain and do it afterwards.
Step 7: Finish
That being said, here is what I did.
1. Used a pre stain conditioner. I highly recommend this, especially if you are working with a soft wood (like pine) or a wood that doesn't stain evenly.
2. Stain. I used a Minwax dark walnut gel stain. You brush it on, wait about 3 minutes, and wipe it off.
3. Minwax paste wax. I chose not to finish the wood with any kind of sealer. I would normally recommend it, but 100 years ago, a table would have gotten rubbed with beeswax and put to use. I'm hoping that I can get some of that wear over time as well. We'll see what happens. If it doesn't wear well, I'll strip the wax and apply a clear polyurathane sealer.