There are packages that are expensive with hundreds of features that are the 'industry standard' such as Adobe Premier --
Then, there are free programs, while not as easy to use or not as featured, will get you by with some needed tasks, such as format conversion, splitting, and/or joining, muxing audio tracks, and so on.
Here are a couple free ones. It's not that I recommend them, but they are free and available. Video processing is always tricky -- there are literally hundreds of format combinations for audio/video and so on. Most sites like YouTube will accept a variety of formats, then convert them to a "Flash Video" so that the Adobe Flash Player (which is the video interface on YouTube can play them.
If you are trying to upload to YouTube, your best chances are by converting your movie to .FLV format prior to uploading it -- this format will be recognized by YouTube and their software will re-encode it effeciently to be displayed on that site.
Here are the apps: (Windows only)
http://www.cinefx.org/downloads/ Xilisoft Video Editor -
http://www.afterdawn.com/softwa...ilisoft_video_editor.cfm SUPER -
http://www.afterdawn.com/softwa.../convert_video/super.cfm DigitalVideo Converter -
http://www.afterdawn.com/softwa...gitalvideo_converter.cfm I have used SUPER before -- it's tricky, but does the job - tons of options. I haven't tried the other applications so you're on your own there --
I recommend the site [url]afterdawn.com[/url] -- this is a site that has been around for years and specializes/targets the digital media world in many formats... You can find tons of information on their forums and in their knowledgebases --
Good Luck --