Photoshop question..? Help!?

Question:

Photoshop question..? Help!?

I have taken a lovely photo of my 18 month old daughter walking through the woods in her fairy costume and another of my 4 month old laying down in hers (Indoors) My question is how can I cut just the image of my 4 month old out of her picture and place her in the other one? I wanted to make her look like a sleepy fairy in the woods!
I know this can be done but have no idea how. Also is it possible to shrink the image of 4 month old to fit better with new picture?
If you can help please put this in real lamens terms as I am a bit of a novice (Obviously!) Thanks!

Best Answer - Chosen by Asker: here is the procedure:
1-open both pics in photoshop side by side
2-place the move tool(in the top of tool box)on the 4 month pic and drag it to the 18month pic,close the 4month pic
3- now you have a new layer(in the layers palette)named layer1,double click its name and change it to:4month,made the same with the layer "background"and name it as :18month
4-make layer "4month" active and use the lasso tool to draw a selection around the baby figure,refine it curefuly(adding areas by pressing shift,deduct areas by pressing alt),then press ctrl +shift+i to inverse the selection
5-press delete,the background behined the baby removed and now you have her body in front of the wood
6-press ctrl+t,resizing box appears,press shift and drag the corner handle into the best fit,press enter.
7-by the move tool move it to the suitable place
8-open image menue ,adjusting,use any option to match colors between the two layers
9-when you satisfied,merge the layers and save it as psd file as a backup,then save a copy as jpg for internet usage...
if you can`t do all this ,send them to me and i`ll do it with pleasure
dhaljasim@yahoo.com