American Recorder Technologies, Inc.. cleaning products 
American Technologies. Night Vision, spotting scopes and binoculars

Benbo. tripods
Benetton bags & cases.
Bogen Photo Corp.
Buhl Industries .
Bushnell Sports Optics.

Canon.
Celestron.
Clear Sight. lens cleaner
Coronado Solar Filters and Telescopes.

Davis & Sanford tripods.

Ewa-Marine. underwater housings

Falcon Safety Products.
Fujinon.

Gitzo.

ITT Night Vision.

Kahles.
Konica Minolta.
Konus Optical & Sport Systems.
Kowa.

Leatherman Tools.
Leica.
Leupold.
Lomographic.

Meade Instruments.
Meopta.
Minox.
M-Rock Multi Bags.

Newcon Optik.
Night Detective.
Night Owl Optics. Night vision binoculars and monoculars 
Nikon.
Nikon. (downloads).
N-Vision Optics.

Olympus.

Pentax.

ROR .-- Residual Oil Remover 

SOG Specialty Knives & Tools, Inc..
Steiner.
Swarovski Optik. binoculars and scopes.
Swift Instruments., binoculars, scopes, etc.
Swiss-Tech Tools.

TeleVue Optics. scopes

Velbon Tripods.

Zeiss. and their Sports. section
Zhumell.
Zing Designs. neoprene covers and straps.

rec.birds. 

The American Association of Amateur Astronomers.
American Association of Variable Star Observers.
American Meteor Society.
American Astronomical Society.
Association of Lunar & Planetary Observers.
The Astronomical League.
International Dark-Sky Association.

Amateur Astronomy.
Astronomy.
Birdwatch Magazine.
Coelum Astronomia., in Italian
Sky & Telescope.  

ACE Index: Manufacturers of Binoculars, Optics, Spotting Scopes, and Telescopes.
AstroArchive.
Astro Imaging Hints. photography with your telescope
Astronomer at Cornell University.
Astronet. information on astronomical phenomena
AstroWeb.: Astronomical Internet Resources 
B&H's Binoculars & Scopes Glossary.
Birding Optics.
Birdwatch Magazine's Optics Buyers' Guide.
Optics for Birding.
Telescope reviews.