Link to patchwork/quilting websites:
http://www.earlywomenmasters.net/quilts/index.html - a lot of blocks, pictures mostly without detailed instructions
Quiltbus - links to great number of blocks with instructions - recomended
Classic Quilt Blocks - with patterns to download
Blockcentral - and its blocklibrary
Quiltaholics - a lot of instructions how to sew blocks.
Quiltiger - blocks with downloadable patterns
Blocks - pictures without patterns
Foundat - blocks with patterns
Free quilt patterns from history
Quilterscache and their huge collection of blocks with instructions
Blogs about patchwork and quilting:
http://ramona-quilter-big-dream.blogspot.com/