help-feel stupid

okay, I am a total newbie, but in the past I would just hit my head against the wall until it worked. tried searching the forums, but I don’t think I know enough to search properly, and this must be a simple problem.
look here: giglife.austinbiel.com

as you scroll down, see how the posts and pictures start going all over the place instead of staying within the width of the body? they start going “under” the sidebar, but when I think I have found the place to lock this in, it doesn’t work.

Stumped – is this a stylesheet thing? it can’t just be the alignment on images, because the text isn’t wrapping either…