Designing a User-Friendly WebsiteThere is a wealth of detailed documentation of computer how-to's at various IBM websites and pages. One series of articles I particularly like offers guidance on website design using open source software (such as the content management platform, Drupal). As long as you don't need edgy aesthetics and unusual navigation at your site, the IBM recommendations provide a solid grounding in how to achieve user-friendliness.
The four phases of website design: analysis, design, prototype, and development
The above graphic gives you an overview of the website design process à la IBM. The article in which the graphic is embedded provides detailed recommendations for each of the four phases of the process.