• 404 Template = 404.php
• Archive Template = archive.php
• Archive Index Page = archives.php
• Comments Template = comments.php
• Footer Template = footer.php
• Header Template = header.php
• Links = links.php
• Main Template = index.php
• Page Template = page.php
• Popup Comments Template = comments-popup.php
• Post Template = single.php
• Search Form = searchform.php
• Search Template = search.php
• Sidebar Template = sidebar.php
• Stylesheet = style.css

http://codex.wordpress.org/Using_Themes scroll down to get to the theme structure section.

http://codex.wordpress.org/Theme_Development

http://codex.wordpress.org/Designing_Themes_for_Public_Release

Theme Tools and Other Resources

These tools and resources will aid you in creating and/or enhancing themes.

Layout

• Blog Design and Layout
• Stepping Into Templates
• Customizing Your Sidebar
• Good Navigation Links
• Next and Previous Links
• Styling Lists with CSS
• Creating Horizontal Menus
• Dynamic Menu Highlighting
• FAQ Layout and Design
• WordPress Index Builder
• Photoshop Template for the WordPress Default Theme

Templates and Template Tags

• Template Files
• Stepping Into Templates
• Stepping Into Template Tags
• Template Tags
• Developing WordPress Themes
• The Loop in Action
• Template Tag Layout in simple to read form
• Anatomy of a WordPress Theme
• Templates and the is functions
• Dissection of a WordPress Theme

Tools and Resources

• Designing Themes for Public Release
• Know Your Sources
• Validating a Website
• Finding Your CSS Styles
• CSS Fixing Browser Bugs
• How to convert XHTML/HTML/CSS to Wordpress
• WordPress Design Sandbox Article
• Working On CSS and the WordPress Theme (using a sandbox)
• From XHTML CSS to WordPress (making a Theme}
• Tutorial: How to Create a Wordpress Theme
• Coevolving Innovations guide to Installing Wordpress (including a Theme) on a web host with Fantastico and cPanel (at Wordpress 2.2.1)
• Tutorial: How to Install a Wordpress Theme
• Working with Multiple Themes Outside of the WordPress Installation Directory
• Theme Test Drive plugin to preview themes

Colors, Graphics, and Fonts

• Kubrickr - Changes Default Theme Header Images
• Header Graphics
• Creative Commons Images
• Image * After - Free Stock Image Library
• Free Icons Library
• Stock.xchng - Free Stock Image Library
• Playing With Fonts
• Developing a Colour Scheme
• Colr.org - For Finding Colors in an Image
• I Like Your Colors
• List of More than 70 Free Stock Photo Sites
• kuler - Create color palettes with this web app from Adobe Labs