If you are looking for a convenient way to download lots of videos from video portals like Youtube, Dailymotion ,etc , you might want to try out the software Free FLV Converter by Koyote Soft. The tool offers a search box that pulls video results from the portal (or all of them) that you have chosen. Videos can be previewed, downloaded and converted into another format.
The user enters a search phrase, selects between all or a single video portal and defines the amount of results that he wants returned. All results are displayed in the main pane with information like name, video description, duration, age and views. You have a choice of downloading single or all videos.