How to Create Realistic, Vector Bubbles - Screencast
"His Majesty the Bubble! In this tutorial we will learn how to create realistic colorful bubbles. We’ll cover numerous techniques and build this illustrations step by step. Set aside a couple hours for this one!" - Iaroslav Lazunov
Here is a link to the written version of the tutorial How to Create Realistic, Vector Bubbles and the video version is below.