NASA’s Lunar Crater Observation and Sensing Satellite (LCROSS) is being crashed into the moon, on purpose, along with the now empty 2.2-ton rocket that launched it this past June. The rocket will crash first, around 7:31am EDT, into the crater Cabeus in the south polar region. It should produce a plume of debris over 6 miles high. That plume is what you might be able to see with your telescope.
The LCROSS will be right behind, having separated from the rocket about ten hours earlier. The satellite will send back live color images of the impact and debris plume, which scientists will be studying for signs of ice, in particular. Only 4 minutes of footage will be available before the satellite itself crashes into the moon, creating a smaller plume.
The crash has been planned for quite some time, and the scientists picked a location that will provide a great angle for Earth-based observers. The crater is also suspected to have plenty of hidden ice inside. The rough terrain of the south pole of the moon and the glancing angle of the sun throughout the entire multi-year sun-moon-earth rotation cycle combine to produce lots of permanently-shadowed niches in this region that could harbor and safe-keep ice from sublimation. (This topic was part of my doctoral thesis work, so it is dear to my heart!)
With the crash happening at 7:31am, American observers in the Eastern Time zone will probably not be able to see much, since the sun will have already risen. The further west you are, the better your chances. For me, in the Central Time zone, the sun has not quite risen at 6:31 (but my kids have), and the moon will be about 70% full (full moon was on October 4th), so we might be able to see something. The moon rises later each day, so it will still be fairly high in the sky at 6:30. You probably will need at least a 10-inch telescope to see the debris plume, and the impact itself will be too small to view.
For those who aren’t in the viewing area, or who have bad weather, you can still watch live on NASA TV and on their website. See http://www.nasa.gov/mission_pages/LCROSS/main/index.html for more information. They plan to show live footage from the LCROSS cameras, telemetry, and possibly views from the University of Hawaii’s 88-inch telescope on Mauna Kea. Should be a good show!