www.ldraw.org
LDraw™ is an open standard for LEGO CAD programs that allow the user to create virtual LEGO models and scenes. LDraw is and always will be offered free of charge.
For official LEGO constructions, LEGO’s CAD program, LEGO Digital Designer, can also be used (with electronic building instruction features). Free download at: http://ldd.lego.com/download/
www.brickplayer.com
Private, independent website featuring LEGO sculptures, mosaics, news, reviews, and building tips & tricks. (BrickPlayer also shows tips & tricks on how to do SNOT building – Studs Not On Top)
www.brickjournal.com
BrickJournal is a magazine that spotlights the many aspects of the LEGO Community. Events, people, and models are showcased in every issue, with a couple of surprises too! BrickJournal journalist Joe Meno is always found at the FLL World Festival.
www.brickshelf.com
Cool LEGO building stuff.
www.peeron.com
More cool LEGO stuff, including a list of parts numbers and names; color chart, sets, building instructions (often old item no longer available on www.LEGO.com)
www.classic-castle.com
For LEGO castle aficionados
www.bricklink.com
Premium venue for individuals and businesses from all around the world to buy and sell new, used and vintage LEGO® through fixed price and auction services.
Often it is possible to find old elements that LEGO no longer has available (LEGO Consumer Service also refers to this website).
www.brothers-brick.com
The Brothers Brick is a LEGO blog for adult fans of LEGO. Started in 2005, it highlights the best LEGO creations from builders around the world.
www.lugnet.com
International LEGO Users Group Network, a global community of LEGO enthusiasts. LUGNET unites LEGO fans worldwide through forums, web pages, and services.