It's best to contact the conference organisers for each specific year. This year you can contact:

• General Chair Correspondence
  gc-2008-at-w4a.info
• Programme Chair Correspondence
  pc-2008-at-w4a.info
• Special Issue Correspondence
  specissue-2008-at-w4a.info
• Web Accessibility Challenge
  challenge-at-w4a.info
• Web Accessibility Challenge Submissions (should be sent to)
  challenge-submission-at-w4a.info
• Camera Ready Copies (should be sent to)
  crc-2008-at-w4a.info
• Visa Requests
  visas-2008-at-w4a.info
• All Other Enquiries (to the Steering Committee 2008)
  sc-2008-at-w4a.info

Remember to change all -at- to @

However, if this isn't appropriate please feel free to contact the W4A Organisation:

Simon Harper or Yeliz Yesilada

Information Management Group,
School of Computer Science,
University of Manchester,
Kilburn Building,
Oxford Road, MANCHESTER,
M13 9PL, UK.

Voice: +44 (0) 161 275 0599

Fax:   +44 (0) 161 275 6236

Email: organisation-at-w4a.info
(Cut and Paste; and change -at- to @)