If you've grown weary of the look of your brick fireplace surround, take note: Even the most inexperienced DIYers can learn how to paint a brick fireplace.
While there are many things that can be included on an OK-to-paint list, most stone fireplaces—limestone, sandstone, river rock, for example—are less amenable and harder to change once you do paint them. If you think you might want to paint your fireplace, make sure it is a brick surround first.
To make sure your paint adheres and dries properly, you'll need to thoroughly clean the brick. Use a wire scrub brush to get any dirt or dust, apply nonsudsy trisodium phosphate (also called TSP; wear gloves and safety goggles), and wash thoroughly with a heavy-duty cleaner. Rinse and let dry. Tape off any areas that you want to remain paint-free.
A stain-blocking, oil-based primer can help protect your paint against future soot stains as you use the fireplace. To apply, lay a drop cloth and apply primer to the entire surface, following the manufacturer directions on the can.
Once the primer is dry, it's time to paint (and maybe paint two or three times). Choose indoor latex paint, either flat, semigloss, or gloss, that is rated to withstand temperatures generated by the fireplace (generally about 200°F), and a roller specifically for textured surfaces. The latter will help in covering the surface of the brick, which is likely not entirely smooth. For any spots that you can't reach using a roller, touch up with a small paintbrush. Apply a second and third coat as needed.
Note: This type of paint is only appropriate for the exterior of a brick fireplace, not the interior firebox. If you want to paint the firebox, you'll need a special heat-resistant paint.