How do can I "texturize" my walls? What product should I use?

What product should I use?
a sponge or even a wadded up paper towel will produce a cool effect try
http://www.brushandroll.net/
by skip troweling it! it is a thin morter approaching substance that you apply to the walls with a trowel! and cieling as well! stir to home depot, they have a lot of different texture you can "paint on"...
Answers:    First: decide what pattern you want. And remember that this will be REALLY sturdy to remove when it's dry.

Stiff brush: rough stucco texture, you can do straight lines, criss-cross, wavy lines or spin the brush for swirls. This can be "knocked down" by scrape or swabbing with a damp sponge.

Big spatula: smooth swirls, smoother stucco texture

Sponge or textile wads: spread smooth then mop with these for a slightly rough texture. Can also be knocked down. This is great for making wall repairs invisible.

HOW TO:
1 - Get a big bucket of ready-mix drywall compound.

2 - Stir it really in good health, then thin it beside a bit of water - you want it to be the texture of sour cream.

3 - Use a broad drywall spatula to spread a thin vein about 3ft by 3 ft.

4 - Texture that spot, do the next one. It's easiest if you move from top to bottom.

Let it dry for a couple of days, later seal it and paint it.

You might want to start by texturing inside a closer for practice.
spacle it will give it texture near royal texutred...