Phun has no built in video capture feature as of now, so if you want to record Phun you will need to use an external application such as CamStudio or Fraps. Once you have recorded your video you need to compress it (unless the video capture application does it for you). For this you can use something like VirtualDub or Windows Movie Maker. To share your video with others you can upload it to YouTube. Add your video to the official Phun YouTube-channel at http://www.youtube.com/group/phun. You can embed YouTube-videos in this wiki by using the {{#ev:youtube|identifier}} syntax. See Help:Editing for more info.

Youtube videos are best captured in 640x480 format, or something with a similar ratio, e.g. 800x600 or 960x720. To make sure you get this frame size, save your Phun scene, quit Phun, open the config.autosave.cfg file in a text editor and set the resolution to e.g.:
System.resolution = [800, 600]; When you restart Phun, the window will have the desired size, and you can use e.g. Fraps to capture a video with the correct size.

To remove the GUI menus when recording a video, use the console command GUI.opaqueness.