Here is a short list of great pages (in alphabetical order) I frequently visit and I thing they are worthy of notice.

For my personal needs, I made a much longer list.

When I want to find something special about infrared photographyy I check WJs Infrared & Photography Homepage or Black and White Infrared Film.

Also:
Catherine Steinmann, Erik Boutilier – Brown, Mario Vidor, Peter G. Balazsy