Smoothing out Drywall? I am looking to decorate my spare room for my new tot....

I am looking to decorate my spare room for my new tot. The walls are a bit messy. We cannot afford to redrywall the walls. I have heard of something call skim coating. While at Lowe's, I saw a product by Valspar called Smooth Coat. Is this the same concept of skim coating?
Answers:    Buy yourself a 5 dollar box of tape mud and a 10 wide sheet rock knife and start troweling on for a moment at a time.just remember to always be a short time short rather than to much.you can always supply more.but to sand off to much is a hassle. It really is very simple, a short time ago take your time. Have fun..use a light (drop cord) and look at what you've done...and you will see the imperfection..bye
There are two main kinds of drywall, Sheetrock and blue board. Sheetrock is gypsum board covered beside grey paper. Its edges are beveled. It is finished with Sheetrock compound and cassette. The edges are taped first and compound is applied over the tape and the screw head. Blue board has a blue paper cover. The blue dissertation is moisture resistant and can be skim coated with plaster. You cannot skim coat Sheetrock. The paper will blister and bubble. Yes this is indistinguishable thing but you will need fairly a bit experience in applying it to have it look nice. If not applied and smoothed correctly it will look repulsive and perhaps worst then what you already hold. Smoothness is the key. If you have restraint and your are able to smoothe it nicely to your wall yourself later it will work, If not than you will have to do a lot of sand and will become quite messy.