Web Forms

Let's start with a classic definition from wikipedia:

A webform on a web page allows a user to enter data that is, typically, sent to a server for processing and to mimic the usage of paper forms. Forms can be used to submit data to save on a server (e.g., ordering a product) or can be used to retrieve data (e.g., searching on a search engine).

So, web forms are really needed nowadays (think about this "leave a comment" feature for the most web 2.0 systems).

Here you will find how to build a web form standards-complaint and accesible (using labels and "for" attribute, for instance).

http://www.sitepoint.com/article/fancy-form-design-css

This is another reference; a study about the usability, design and programming about the web forms:

• Hover, active, focus - effects in use?
• Help, support, tooltips: static or dynamic?
• Help, support, tooltips: where are they placed?
• Input validation: static or Ajax?
• Design of error messages
• Is it necessary to confirm the e-mail?
• Is it necessary to confirm the password?
• Is captcha in use?
• Cancel-button in use?
• Alignment of the submit-button
• Thank-you message
• Further findings
  

http://www.smashingmagazine.com/2008/07/08/web-form-design-patterns-sign-up-forms-part-2/