Here are a few methods I would use. I would certainly recommend doing it in Camera Raw, since you can fine tune a lot of adjustments at once.
If you have truly blown out areas, they will not be recoverable, but the main thing you'll want to do is lower the overall exposure and probably bring up the black point so that you have good overall contrast (histogram covering all or most of the range of exposure values, depending of course on the subject matter).
Basically you want (for most images) to adjust the sliders so that you have a histogram that covers the full range of values. Since your washed out images will have the histogram bunched to the right, you want to lower the exposure (and/or use recovery slider) to bring back the brightest areas off the right edge of the histogram. Then use the blacks slider to set the darkest areas to black (if suitable).
In Camera Raw, you can also drop the brightness, add a curve or boost the saturation as needed. You may still want to do levels/curves adjustments in photoshop, but Camera Raw adjustments should give you a good starting point.
Using Camera Raw - no spot removal or denoise :)
Multiply Blend Mode
A common method that I've seen is to simply add a levels adjustment and set the blend mode to multiply (without making any changes to the levels slider). And repeat as necessary to restore some contrast. I guess that's a simple method, but I'd rather do it in Camera Raw where you have more control.
Using a levels adjustment layer with multiply blend mode. Not quite as crisp as the ACR adjustments.
Curves Adjustment Layer
If truly washed out, you may want to reduce the exposure in Camera Raw or with an Exposure adjustment layer, then:
Add a threshold adjustment layer. Move the sliders to determine the brightest and darkest areas of the image.
Add a curves layer, and then use the black and white eyedropper tools to set the black and white points as found in the first step.
Throw away the threshhold layer.
This will make the blacks truly black and give you that histogram that covers the full range of exposure values (assuming your image ought to contain full blacks and whites, i.e. not the picture of a white cat on snow).
With most images I would aim to get the blacks near the left edge, but that would result in too much loss of detail in the shadows in this image.