If the shows are being sold as 4:3 and watched on a 4:3 display, the AppleTV should not be doing any pillarboxing. Unfortunately, this thread seems to suggest that AppleTV in fact does not support 4:3 displays. Many newer 4:3 displays offer a 16:9 mode (my 4:3 HDTV offers this, as well as a zoom mode that works at HD resolutions) which allows the TV's to support the AppleTV's 16:9 output, but your Sony XBR does not appear to be one of these. The Toshiba we have in the bedroom is also not one of these, so my scheme for using an AppleTV or two and a video capture card in my TV to build a whole-house DVR setup will have to get shelved...