Sadly, icefilms has been a mess for like 10 days or so. Right now only the vds (old site) is working. Hopefully they will get the www version straightened out soon. there are multiple threads about this on the xbmc and fire core websites.
Hmm, I just use handbrake help adding videos/movies to my ATV, and now the ATV is being our family home media centre!
For Apple TV tips and tricks, I got much from this Apple TV wiki: http://wiki.awkwardtv.org/wiki/AppleTV_2