Best practices, standards and guidelines, there is a huge difference between all of these and usually each can be take in a particular context. For example, fo this particular item, there is not standard, especially not a W3C standard in regards to form field naming, however, when taking into consideration items such as acessibility, e.g. Section 508, there are standards.
http://www.access-board.gov/sec508/guide/1194.22.htm
Granted, these are not around the names per sey of the fields themselves but rather how you would construct the label of the names to allow for consumable accessibility (screen readers).
What naming standards such as this come down to is that you should scope out requirements and do tests around usability/accessibility - for your organzation. This means you should name fields (labels and actual controls) in a way in which your organization can easily consume and understand them.
A simple example, at one organization the term 'address' may fly for street, in another it would be confusing and interpreted as the entire mail address.