..::Pixel bubble Tutorial::..
I am going to teach you how to make bubbles in MS paint, but you can use any graphic program
First open MS paint. Make the size about 100x100 to give you room if you want to make alot of bubbles.
Using the color pallet use the first color and make the outlines of the bubbles using the round shape tool 
Fill the bubbles in with color #2
now use colors #3 & #4 to shade the bubble.
You now have bubbles and this is what they should look like.