Chris Leck , Jun 12, 2004; 01:55 a.m.
You could try patching the areas with the patch tool, touching-up with the healing tool. There's a more sophisticated technique using custom patterns made with Photoshop's Pattern Maker (see Martin Evening's book, the chapter on repairing images).
If areas are partly blown, try copying to another layer and experiment with multiply blend mode to build density. Michael Kieran discusses this in his color correction book.
Another thing you might try is not blowing out the areas. Expose for the highlights. Take test shots and use the highlights display function if your camera has one. When areas are blown, they're gone and it's less graceful even than slide film. Of course, blown areas are not always bad, e.g., blown specular highlights or white portrait backgrounds. I've been obsessive about not blowing highlights at times and ended up with mostly underexposed images (which require extra work and may exhibit banding if not fixed carefully).
One last thing you might try is the contrast setting, if your camera has one. I set this to lower contrast on my D100 when I am shooting very contrasty subjects, such as stage performances or dance. It gives me more leeway to allocate the existing contrast later, via curves.