Don't Be Inaccessible
Heal Your Church Website has a nice article today about churches that have problems with being inaccessible.
Some of the specifics that Dean mentions:
Bad Markup
Browser-Specific Navigation -- Things that only work in certain browsers
Charging Money for Sermons
Poor Navigation Hierarchy
Too Much Flash
He gets into more detail about why each item can cause problems. It's a good read - check it out.