Google Webmaster
Google's resource for web developers which can help you improve and understand your site, connect with visitors and find out what to avoid when it comes to SEO.
e-consultancy
Provides information, training and events on best practice in online marketing and e-commerce.
Website Accessibility Guidance
Some key guidance on how to develop a website which is user-friendly for disabled people. It was developed in a joint initiative between the Disability Rights Commission and the British Standards Institution.
Search Engine Strategies
These guys hold search engine marketing events throughout the year. Some of the industry's top search experts speak at these global conferences.
SEOmoz
An online community for the search marketing industry, providing an SEO services marketplace, a popular SEO blog and SEO tools.
Great all round resource with plenty of useful content about search engine marketing and search engine optimisation.
SEO Chicks
'A blog with attitute' written by a group of female SEO consultants. Contains great tips, info and news from across the search industry.
Launch Marketing
A friendly start-up firm offering small business marketing packages to other start-ups