YouTube, MobileMe Gallery, and iPhonethree great ways to share your favorite videos. Don't forget that YouTube requires setting up a free account at YouTube.com, and MobileMe Gallery requires a paid MobileMe membership. If the MobileMe Gallery feature was the only thing a membership gave you, I'd still think that it's worth the price. But it includes lots of other great features in addition to the beautiful Gallery feature, so check it out.
Shooting video is fun, but carrying a video camera with you all the time isn't. That's why I carry a Flip video camera with me almost everywhere I go. It's not much bigger than an iPod mini, shoots high-quality video, and fits in any pocket. It's so small that I often forget it's there. If you want to make sure that you never miss a shot, and you prefer higher quality than your mobile phone video can provide, consider buying a Flip.
Remember, your movies don't have to be long or fancy for friends and family to enjoy them. So have fun sharing!