A little late (yea, I've been away from the blogosphere for a bit) but Justine had a great funny post here about How to Write a Novel
"You may get stuck along the way, and have no idea what your characters should do next. Raymond Chandler says that’s when it’s time to send someone in brandishing a gun. Sending in a vampire also works. Or you can set something on fire, have a long lost relative or best friend show up, have your protag lose all their worldly goods, or discover that the lovers are actually siblings (ewww!)."
As for me, I've tried writing via outline, but I can't. I'm very much of an organic kind of a writer, and I've always been that way. Even as an undergraduate, writing papers, I would just sit down and write, and not have any idea what the heck my thesis was, and when I finally finished the paper, I would read over, and go, OH that's what I'm talking about. I'd add an intro, and a conclusion, tweak it a bit, and then it'd be done. (Now I'm not saying that that's necessarily the most efficient way of doing things, and trust me, it involved a lot of hair-pulling and tears in college as I struggled to find my way but it works for me).
As I write fiction, I find myself doing the same thing. I write scenes, interactions, and usually not in sequential order. I think I'm beginning to realize that when I get bogged down in the middle of a manuscript (as I am now), I just have to keep moving ahead, skip over that part and write the next thing, even if it is the end, and come back. Of course, this just makes it all the more difficult for my poor crit partners.