Alex, I have PSE 2 & 4. Here are a couple of ways to make a selection: 1- PSE 4 has the magic extractor. 2-Both of them have the magnetic lasso tool. You will need to feather, grow, etc to get exactly what you want either in or out.
I will erase the sky and add in a new one by making a new layer and combining them.
I have made a new document that is just what I call a basic sky layer. I adjust the hue & saturation to my liking and then combine them.
It is quite tedious if there are a lot of trees with white spots that will have to be selected with the magic wand and then filled ibn with the paint bucket.
I hope some one comes up with a better way for the both of us.
ANYBODY?

Ronk,

There is one new feature in Elements 4.0 called the Magic Selection Brush that I discussed in the July issue on page 154 that worked quite well to make selection easier. Not perfect but a lot better than most of the "easy" selection tools I have tried. Give it a go when you can and take some time to play with it a bit and I think after you get the knack of it you will find it useful.

Thanks!