This modifies the spacing between words. It takes values in in, cm, mm, and px, among others. This has a value of 20px.
Letter-spacing does the same thing, except to each letter. This has a letter-spacing of -2px!. If you can't read it, it says "This has a letter-spacing of -2px!" Yes! The letters overlap, and so can the words with a big enough negative value.
As with most keywords you'll use, you can also give them the value normal which un-does any inherited value.
This indents the first line of text that the element has, such as the first line of a paragraph. It accepts any of the above values, and it can also be given a negative value to push the text to the left of the left margin.
this increases the spacing BELOW each line. This can be done in three different ways. It can be set with the measurements above to give that exact space between each line. It can be set with just a number, too. When you do this, it takes the size of the font (or the font-size value if you have it set) and multiplies it by the number. The result is the new spacing between lines. And you can use percentage values. They work the same as just putting a number. It multiplies the font size by the percentage and the result is the new line spacing. Yes, you can overlap lines with this, too.
Text-align aligns the text with these four values; left, center, right, and justify, where left is the default. This keyword may not work on certain elements, but I'm pretty sure the most up-to-date browsers have it fully implemented. Just test it to see if it works first.
Vertical-align is what you expect it to be. The value top aligns the top of the affected element with the top of the element that contains it. The value bottom aligns the bottom of the element with the bottom of the element that contains it. The value middle aligns the middle of the element with the middle of the element that contains it. Finally, sub and super make the text subscript and superscript. There is more to this one, but I like to know what I'm talking about when I teach a lesson, and quite frankly I don't know what the other values are supposed to do. The main application of this property as I see it is aligning the text in tables, but that doesn't mean it doesn't have other applications.