Photoshop is an excellent application for web designers. No matter you are beginner of expert of Photoshop, you can easily get tutorials and resources by using the search engine.
Most of the theme developers/designers will done their website design using Photoshop, and then slice and convert them into CSS/HTML template. Here, i had collected 30+ easy to follow Photoshop layout design tutorials. You can follow them step by step to learn how to create a website layout design by using Photoshop.