If you want to know what's happening in the scene, this is the place you should go to. On the boards listed below, you'll find announcements of releases, demo recommendations, background information on sceners and groups and piles of photographs taken at demo parties.
Another big demoscene board. Pouet is especially good to check out demos and the like and comments on all important productions in the scene, and it's famous for its logos that are made by sceners that love Pouet.
http://www.pouet.net/
Bitfellas is one of the largest and most active scene portals today. Beneath a large forum it features latest news from the demoscene and a lot more.
http://www.bitfellas.org/
scene.org is often called 'the core of the demoscene'. It hosts almost ANYthing ever released in the demoscene, from little intros to huge videofiles, from serious productions to funny party livecuts. If you can't find what you're looking for on scene.org, it's probably just an hour or two old, or you made a typing mistake.
http://www.scene.org/
'Stop making that weird face!' Slengpung hosts a huge archive of demoscene event pictures. You've been to a demoparty and photographed? There is a good chance that you'll find your face here. Slengpung isn't only fun, it gives a good impression of how demoparties look.
http://www.slengpung.com/
Scenesight sees the demoscene from outside itself and and tells what's happening at science festivals, on radio stations, or in print media in collaboration or solely from the heart of the demoscene. This is one of the best places to go if you want to know what impact the demoscene has.
http://www.scenesight.org/