The Ambient Music Guide is a well-established overview of the entire history of Ambient music and its relatives. I think it would be safe to say that the owner has less pop-oriented tastes than myself.
EnigmaMusic.com is the clear hub of English-speaking Enigma fandom. They have a very active message board.
Many of the biggest artists featured on this site are signed to major record labels, and many of the smallest aren't signed to any label at all. There are, however, a few smaller "niche" labels that specialize in Nu Ambient artists.
IntentCity Records is a very specialized label that supports many of this site's most Enigmatic artists, including Lesiem, Magna Canta, Waterbone, and Mysteria.
Neurodisc Records has an extensive roster of artists from every corner of electronica. As far as Nu Ambient is concerned, they're something of Ambient Pop specialists, representing both Sleepthief and Blue Stone. They also represent some fantastic instrumental acts, including Amethystium.
Founded by brothers and producers David and Steve Gordon, Sequoia Records puts out many chill-out compilations, must notably the Buddah Lounge series. They're also the home of TYA and former Enigma co-producer Jens Gad (including his Achillea project).
Everyone should check out Ishkur's Guide to Electronic Music at least once. You won't find "Nu Ambient" specifically, but "New Age", "Ambient", and particularly "Worldbeat" seem to have us covered well enough.