The best plugin I tested for this purpose is called “Neat Image”.

It gently remove noise (especially color noise caused by high ISO) without completely destroying the sharpness.

The program has probably already a profile for your camera so that it knows exactly what it must do to have a good balance between noise and sharpness.

If your particular camera model is not listed in the database can easily create your own profile by letting the program analyze a picture.

I recommend the program, have used it for years and when it is needed, it is invaluable.

Unfortunately, it is not completely free, it costs about 40 USD but is well worth the money.

It is also available as stand-alone programs, but the plugin works great in Adobe Photoshop Elements (and of course in “large” Photoshop).

We may at some point “play” little with the program a club night later this fall.

Link: http://www.neatimage.com/