How do I clean dried latex paint from paintbrush in order to reuse the brush?

I always just run water over them until they are clean and soak it in turpentine if it started to harden. I looked it up and found this site
Cleaning Paint Brushes (http://www.askthebuilder.com/686_Cleaning_Paint_Brushes.shtml)

Turpentine will not loosen dried latex paint from a paint brush; turpentine is used for oil based paint clean up. Paint brushes used in latex paint should be cleaned right after use, otherwise forget it. If I paint and then want to go back to it the next day, I put my paint brush in a zip lock bag so the paint won't dry out. Likewise for the roller... in a plastic bag so I can use it without it drying out with the paint on it.

Soak your dried paint brush in laquer thinner or paint stripper, it will be like new after you comb out the crud. I have a few China bristle brushes I love but let them get dry, they are like new again. No need to ever throw out a brush again.

What kind of bushes is it that you are inquiring about? There are different methods of cleaning depending on the type of brush that you are using. For instance, are the filaments out of which the brushes are made some kind of animal bristles, or man-made, such as nylon or polyester? Some of the best brushes that I use, I have used for decades because of the proper care for them after they have been used.