APA Web Guide from the OWL at Purdue
A comparably thorough and easy to use guide, only for APA.
Style Wizard
This interactive site guides you through writing individual citations one step at a time. Steps for each part of a citation explains how information for that part should be entered.
Citation Fox
Contains templates and examples for over 500 different resource types, sorted by type of resource (book, journal article, etc.) Provided by the University Libraries at University at Albany SUNY