Assuming the phone has a web browser, post it on the web (e.g., YouTube), and browse to it on the phone... Or put it on your own web page and just use the URL to reach the video.
Might depend on your Phone OS. I'm an old fart don't have a cell Phone but I do have an iPod while I like the iPod I hate Apple's IOS on the Pod and iTunes on my PC. Apple goes out of its way to hide its file system there are apps like the one I user to share files beween my PC and the Pod. I use AirShare. I start Airshare on my iPod the I can map/mount it onto my Windows PC as a drive. I can then use the iPod as a disk create delets copy files to it. AirShare provides file viewers so tou can use the files on the iPod. Vied Images, PDF, some video file types etc.