this is a section of the texturing forum reserved for links to useful texturing tutorials, of which there are lots, for unfortunately there's a lot of cr*p out there too.
SO... you can post the most useful ones you've found here
oh, and please credit the artist/writer that wrote it.
I will also gather up any links you guys post here, so they're easily accessible
"top ten tips of texturing - Jeroen Maton"
"texturing tutorials" - philipK
"Hard surface texture painting" by Stefan Morell
the polycount wiki!
upsize your photo ref/ textures
kinda like this, but youtube user LkasArt. Photoshop
the game-artist.net general modeling and texturing tutorial thread
De-Constructing "Demon Throne" - A Postmortem / Tutorial Video Series by Jason Lavoie