MyStar is a software available for download. Either by installing it or in the website you can get the star charts and animations for any dates or times in the past or future.
Hands-On Universe™ (HOU) is an educational program that enables students to investigate the Universe while applying tools and concepts from science, math, and technology. Using the Internet, HOU participants around the world request observations from an automated telescope, download images from a large image archive, and analyze them with the aid of user-friendly image processing software.
A great source of astronomy images, videos and material.
Good site having details from basics of astronomy, glossary of terms to deep sky observing guide. Also it has links to many more sites on astronomy.
A multimedia tour of the solar system
Online astronomical magazine