I use Photoshop CS4.
Hey, did you know you can get Photoshop products for 80% below retail at the Adobe Education Store. -- That is if you are an educator or a secondary student? Just thought you might be interested. (That's the only way I could do it.)
Otherwise, I would use Paint Shop Pro Photo X2 Ultimate
OK, so I came across this new plugin for Photoshop (and it's not just a plugin - there is a stand alone version if you don't have Photoshop.) It's called Green Screen Wizard.
Have your heard of Chroma Key processing? It's been used in video for years. Like when the weather dude is standing in front of the weather map, but he really isn't. Instead, he is in front of a green screen, and they can superimpose his body in front of the weather map.
It's really funny when he wears a green tie, and you can see the weather map where the tie is.
Well, the makers of Green Screen Wizard have taken this chroma key concept and created software that is for photographers.
It is a great product, making the process sooo much better than "cutting" out your model and "pasting" him or her into a new background. I have done this so many times, and it takes quite a bit of skill and time to do it right. Even then, it may look like unnatural.
Here's one I did using the cut and paste method. It's my granddaughter standing in the doorway of a 10" tall Lincoln Log house. Took me probably an hour.
However, now all I need to do is put the subject in front of a green (or blue) screen, shoot the photo and process the image with Green Screen Wizard. The makers have used a formula that actually integrates the two images together so it does not look pasted.
I suggest you give it a try. You can download a free demo of Green Screen Wizard to try it out before committing your hard earned cash.
Of course, you will need a screen. Green Screen Wizard also has a screen you can buy (surprise!), but I have checked prices, and theirs is actually cheaper than any I could find on Amazon or the photo sales sites.
Oh, did I mention that this is NOT just a plugin for Photoshop. You can get the software as a stand alone application, too.
Read my real review HERE. There is much more information and some great sample photos.