Can websites be locked down on the iPad?
apple.com, ipad for business:

http://www.apple.com/ipad/business/resources/

From disabling Safari completely (allowSafari=false) to functional options:


Enable autofill: When this option is off, Safari doesn’t remember what users enter in web forms.
Force Fraud warning: When this option is off, Safari doesn’t attempt
to prevent the user from visiting websites identified as being
fraudulent or compromised.
Enable JavaScript: When this option is
off, Safari ignores all javascript on websites.
Block pop-ups: When
this option is off, Safari’s pop-up blocking feature is disabled.
Accept cookies: Sets Safari’s cookie policy. Choose to accept all
cookies, accept no cookies, or reject cookies from sites not directly
accessed.


Thereby you can limit the iPad to only apps (and webapps) installed by you.