Melonpocky,
Not dumb--just thinking! And we all had to learn (and are still learning) about gardening. Welcome to a great pastime/hobby/obsession.
Rootbound refers to a plant that has outgrown its pot. The pot's contents are mainly roots and little soil. The roots tend to go around in circles, or form a mass at the bottom of the pot. The cure is to gently pry the roots apart and spread them when the plant is put in the ground, or if that is impossible (in a REALLY root-bound plant)make an X-cut in the roots from the bottom about 1/3 of the depth of the pot. Being rootbound will eventually kill a potted plant, and if planted in a rootbound state, the plant will not thrive as it should, and could die.
As to "bury up to the leaves"--when planting tomatoes, it is best to get all the stem up to the first leaves (the little ones that first appear and are usually smooth-edged, not notched like secondary, true leaves)into the ground. I make a trench and put the tomato plant in the 3" to 4" inch deep trench, then put a cardboard collar around the plant, making sure it doesn't interfere with the buried stem. That takes care of cutworms. Earwigs? I have no idea.
When you put your plants in the ground, try to do it on a cloudy day (yeah, in Texas!) or late in the afternoon so they will have as little direct sunlight to contend with right away. Water in well (not overhead, but at ground level) and don't worry if they look a little limp for a day or two. Keep an eye on them, and if we have high winds, you can protect them with bottomless pots (cut the bottom out of a 1 gallon pot or the top and bottom out of a plastic juice container and put one over each plant. My neighbor's garden looks like a Sunny Delight plot!
Next year, try watering your seedlings from the bottom only. They learn to put down roots, and absorb only what they need. It is also easier for you to tell if you are overwatering because they will be sitting in water instead of drawing it up.
Now I've told you more than you wanted to know--I just want wish you luck with your garden, enjoy the fruits of your labors, and keep trying if it doesn't work out perfectly the first time.

Hello! If you look at the link below, someone last month brought up cut worms & how to deal with them.. Open up the link & scroll down the page. You'll see a pictoral of someone cutting straws to put around the stems of plants.

Here is a link that might be useful: Cut Worms

Thanks for the info, Marlin and Booberry!

Marlin-- I do plan on keeping some of my tomatoes in containers (I can't just abandon the ones that don't make it into the garden!) so is root maintenance something I will have to do regularly? Also, I am not entirely sure what you mean by "x-cut" in the roots-- like, cut the entire root ball to a 1/3 ways up with two cuts?

And we've been having some awesomely cloudy days recently, so I'm hoping that it will stay that way when it comes time to put my babies in the ground! And lol at the Sunny Delight garden!

I'm not sure if you haven't heard of earwigs or just don't have them in your garden, but in either case you're lucky. Even if they innocuously live amongst your plants without doing harm, they are the creepiest little things ever. It's difficult for me to not recoil when I see them wiggling over the ground.

Booberry-- I had looked at that thread and I love the drinking straws idea for cutworm defense. It looks like a little project in which I will have to employ the assistance of the boyfriend :D I'm guessing that the straws don't interfere with root development or transpiration through that part of the stem? I can just imagine the stems rotting under the straw just to spite me.

Your plants won't need those straws forever, just until they are big enough to not get cut down.... :) I usually don't plant out tomatoes until they are big enough that it's not a problem. They are usually a foot tall.

I also bury most of the tomato plant. all thos whiskers on the stem can become roots, and they aren't really going to start producing much flowers/ fruit unti lit really gets good and warm, and trust me, they will shoot right up out of the ground in no time!

Melonpocky,
You understood the "x-cut" perfectly. Two cuts 1/3 of the way up from the bottom--but this is for plants so rootbound that you can't tease roots loose from the ball. If you are going to have container tomatoes, put them into the biggest container you can right off the bat, then you don't have to worry about root maintenance. Taking a plant out to do root maintenance will set it back. Usually that is done only to divide perennials. Be sure you want to devote the extra fertilizer and water to container tomatoes. They have fewer resources than in-the-ground tomatoes and will need more from you. You are going to have a fantastic garden!