Matzah, or unleavened bread, is the traditional food of Passover. As the story goes, the Jewish people were in such a hurry to leave Egypt that they did not have time to let their bread rise, hence Matzah. Today, Anna went with her class to bake matzah at a local event sponsored by Chabad. There are often events like this in major cities or Jewish centers throughout the country around this time - check your local Jewish paper or online for information.
Matzah needs to be made in a certain way, with restrictions on time and ingredients and other details. Although fun and exciting, we will not be using Anna's matzah for our seder. But not all other matzah is the same. There is machine made matzah (the square or rectangle ones with the holes in perfect lines) and then there is hand made matzah. The term "shmurah" refers to the idea that the matzah has actually been watched over since the time that the wheat was cut from the field to ensure that it did not mix with any water until the proper time. Nowadays, there is a nice variety of matzot (plural of matzah) available, including matzah made from different types of grain besides wheat - very important for people with allergies or digestive issues. For exactly what you should be using at your seder table, contact your local rabbi.
Here are some resources on the web for ordering matzah. Many people have the tradition of eating hand-made matzah at their seder table, and ordering through the internet has made it available to places where it is not necessarily sold locally. Don't put off ordering or shopping around for much longer! This is one of those times where procrastinating ends up costing you a trip to every supermarket within a 20 mile radius as you search for one more can of kosher for Passover tomato sauce, cooking oil or -- yes, even matzah.
Matzah Online - Sells shmurah matzah made in Israel and America. Whole wheat, organic whole wheat, spelt and oat matzah available.
Soft Matza - Traditional matzah eaten by those of Sephardic descent. Interesting site!
Avi Glatt - This site is like a full online kosher supermarket. Really tempting items available. As far as matzah is concerned, this looks like a good site to check out if you are partial to a specific brand of machine made matzah that your local supermarket is out of because, like me, you have not yet considered food shopping for the holiday.
Kashrut.com - Offers an overview of the entire topic of matzah, as well as the different types and explanations.