American Society of Media Photographers Best Practices and Workflow http://www.dpbestflow.org/

Nikonians
http://nikonians.org

Nikon USA Learn and Explore
http://www.nikonusa.com/Learn-And-Explore/index.page

Thom Hogan Nikon Guru
http://bythom.com

Canon Digital Learning Center
http://www.usa.canon.com/dlc/controller?act=HomePageAct

CanonShooters.com

Canon Guru here...

The Luminous Landscape
http://www.luminous-landscape.com/index.shtml

DPReview.com

PhotoFocus Podcast and Blog
http://photofocus.com

Depth of Field Online Calculator, iPhone app too
http://www.dofmaster.com/dofjs.html

Sensor Cleaning Info
http://www.cleaningdigitalcameras.com/methods.html

Lens cleaning Info
http://www.digital-photography-school.com/how-should-i-clean-my-dslrs-lens

Landscape Shooter's Super Sharp Focus Tips:
http://digital-photography-school.com/how-to-get-super-sharp-landscape-photography-images/

RAW vs. JPG: Luminous Landscape Article - DPS article

PhotoForum.com's Tone Scale. It is best to calibrate your monitor of course but at least make sure you can see all the tones in this helpful graphic:

compare to Adams' Zone System: