Instructions for knitting backwards
Experiments in jogless stripes by Judy Gibson
Using a yarn winder from Knitted Threads
Using a ball winder from
How to make a pull skein without a yarn winder
Kitchener stitch tips from Planetshoup
More Kitchener stitch tips from Knitting Software
Even more Kitchener stitch tips from Mary Ellen Meisters
An alternative to using the Kitchener stitch

How to knit from the Craft Yarn Council of America
How to knit from Cuddles
How to knit online videos from Common Threads

Animated knitting techniques
Tricks 'n' Tips from Tradewind Knitware; includes information about the mattress stitch, intarsia, blocking, swatches, and more
Borealis Sweaterscapes has several pages of good instructions (with photos), including intarsia, short-row wrapping, making shoulder seams, making invisible seams, and picking up stitches.
Lots and lots of technique descriptions (too many to list!) from Flor
Knitting tips from Easy and Cheap Crafts
Sock knitting techniques