Web consultancy and training organisation specialising in accessible websites, the designer of the SAIF website and the co-author/editor of this guide.
http://www.jimbyrne.co.uk
The RNIB has a range of very useful guidance notes as part of its See It Right accessible websites campaign. These guidance notes contain lots of advice about building websites that do not exclude visually impaired people.
http://www.rnib.org.uk
WAI offers a vast range of resources that will be helpful whether you are a complete novice or a technical wizard, including accessibility checkers like WAVE.