NASA
Nasa: Droplets: Kiwi Kids Cloud Identification Guide [Pdf]
Learn all about the different kinds of clouds in our atmosphere, how each forms, and specific details of each. Colored photos and an altitude cloud chart are included. PDF (requires Adobe Reader).
Globe
The Globe Program: Do You Know That Clouds Have Names? [Pdf]
Did you know that clouds have different names? Each cloud in the sky has its own unique form and it has a particular name based on its shape, where it floats in the sky and the type of moisture it contains. Learn here all about the...
National Earth Science Teachers Association
Windows to the Universe: Cloud Types
Windows to the Universe provides a table with information about each cloud group, base height of each of the cloud groups, and links to information on the individual cloud types associated each group.
Other
Northern Michigan University: Stratus Clouds
This succinct site draws a connection between stratus clouds and types of weather. It also explains how these types of clouds are formed.