The internet is full of resources of interest to the amateur astronomer. Over in the Lunar Observing forum we have put together a list of links to web sites/pages of use to Lunar Observers that has becomes a large and useful resource. I would like to see such a resource brought into being for this forum as well. Toward that end, I have stuck this post to the top of the forum, and begun our list of online solar observing resources with a link provided recently by David W. Knisely :

Observing the Sun in H-alpha

NASA: Solar Physics

NOVAC: Understanding Hydrogen-Alpha Solar Filters

Resonant Spaces - H-Alpha Etalons by Colin Kaminski

Sungazer Reference List

Dave Groski's Solar Page

Big Bear Solar Observatory

National Solar Observatory

NWS Space Environment Center

Astro-Nut.com Solar

Raban Systems Solar Current Solar Image

Observing the Sun with a Spectroheliograph

Solar Photos from Germany

Cemax Eyepiece Review

Ha-Observing on a budget by John Crilly

ALPO solar section

Please add links that you know of and have found useful. I will periodically go through what is posted on this thread and add it to a master list in this post for convenient access.