The most basic object to display text is a FlxText. You can easily set properties such as text, color, alignment and more. It is an extension of FlxSprite, which means, you can do a lot of the same things with it.
// create a new FlxText
text = new FlxText();
text.text = "Hello, World!"; // set text's text to say "Hello, World!"
text.color = FlxColor.CYAN; // set the color to cyan
text.size = 32; // set the text's size to 32px
text.alignment = FlxTextAlign.CENTER; // center the text
text.setBorderStyle(FlxTextBorderStyle.SHADOW, FlxColor.BLUE, 4); // give the text a 4-pixel deep, blue shadow