There are a lot of resources for patients on the Web, and the links below will take you to a few good starting points.
Not all web pages have good reliable information so be careful out there...

General Dental Council
useful as it has a searchable index of all the registered dentists in the UK

The Tooth Fairy
this page is by an American hygienist

Dentistry for Pets
a professional site sponsored by Hills.

The American Dental Association
This is their subsite specifically for patients.
There is a lot of well presented, reliable information

Dental Health Pages
Website of the British Dental Health Foundation that organise Smile Month and Oral Cancer Month each year
There is again a lot of well-presented information on dental health.