Tags : http://en.wikipedia.org/wiki/Tags
Tags are descriptors that individuals assign to objects, in the practice of collaborative categorization known as folksonomy.

Categories : http://en.wikipedia.org/wiki/Categories

Folksonomy : http://en.wikipedia.org/wiki/Folksonomy

So, whats the big difference between Tags & Categories? Tags can be categories, but categories cannot be tags.
Tags can span across multiple categories.

Tags are “many to many”, Categories are “one to many” says Brother Kingsley, who recently switched over to Tags from Categories.

Tags |