Originally Posted by DannoXYZ

yeah, you should be able to move around the pack without yelling or making people move aside for you. If someone leaves a gap, then that's their problem. Even a small gap like 3-4 feet is enough to squeeze into. You obviously can't move sideways into that gap or else you'll overlap both front & rear wheels. But what you can do is "back up" into that space. Start slowing down and when your rear-tyre has cleared the rear-tyre of the guy next to you, slowly move over. This will shove the guy behind backwards and he'll increase his gap. By the time your front-wheel is next to the rear-wheel of the guy next to you, your spokes should be rubbing on his derailleur. Then gradually drift backwards and sideways until you're directly behind him.

Another good way to grab a wheel is to sit on the outside when going around a corner. When coming out of the corner, don't drift quite as wide as the guys ahead of you. They'll end up moving sideways directly in front of you. Hold that wheel and move up.