http://www.theskidiva.com/forums/

That's trended a bit more towards downhill, though there may be some posts about xc. It's a new site, and somewhat small but seems nice. The site I like to frequent about all things snow is http://forums.epicski.com, but again that's trended a bit more towards the downhill and backcountry end of things (and snowboarding too).

I've always wanted to try xc, just for the cardio benefits of it, but it's rare when theres a day that I don't want to go downhill and I'm near an area where theres xc trails and rentals. The days I do end up having free I'm much too wiped to do anything physical and am more into recovering for the next day of skiing!