Windows Movie Maker is a great tool for patching together, cropping, adding transitions, etc. to come up with some very nice self-published movies. But the new Windows "Live" Movie Maker beta has stripped out all movie editing capability and left the limited ability to simply stitch together movies and photos. Most people shoot lengthy movies expecting to crop out just the "good stuff." That was possible with WMM but not with WLMM beta. You can’t edit the video. regardless of the claim being made on the product page.
”Import and edit your movies so they look great “
Movie Maker beta – Windows Live