In Europe, at least, this comes under the Unfair Commercial Practices Directive: http://ec.europa.eu/consumers/rights/ Here's a more friendly synopsis: http://www.seomoz.org/blog/new-uk-law-criminalizes-stealth-marketing-techniques

... is a great book by Steve Krug (no connection, just a satisfied reader). He advocates *very* simple usability testing and gives practical advice on how to do it in Chapter 9: "Usability testing on 10 cents a day". I've followed the advice given and it worked well. Like the useit.com suggestions above, Krug's site is useful too: http://www.sensible.com/