At the time of your talk, put your presentation on the web or bring it on a CD or USB key. You should show up early to put your presentation on the computer (or email it to me ahead of time). Doing so before the start of the session as opposed to right before your talk will speed things up for everyone.
You are expected to attend as many talks as possible, and are required to attend those during regular class periods.
You should consider your presentation's scheduled time slot final unless you have a conflict that you absolutely cannot change. This is to prevent constant modifications of the presentation schedule, which require alterations to everyone else's schedules.
Unless otherwise noted, each talk will be 15 minutes, plus 3 minutes for questions. Hence a total of 18 minutes is allotted per talk. However, this is only an approximation! Don't assume that your talk will start exactly at the time implied by the given schedule.