Can someone let me know if there is a plugin / application that will let me upload videos to site. And when users want to access the video they will prompted for login and password
The best place to look for extensions is the JED (Joomla! Extension Directory).
AllVideos is by far the most popular video player extension available for Joomla! since it is a very lightweight plugin (no components or modules).
What I would do is create a category of articles that is restricted to registered users. Then, create articles inside that category with the videos embedded.
I have recommend Joomla videoplayer extension for joomla. excellent free support,live chat, forum and more features. Easily understandable coding structure, easy to change as own..