I have one video on youtube - Vernon Corv (that's me) "Who Ya Gonna Blame". Check it out.
I have a pretty good Canon HD camcorder, and edit in Adobe Premier Elements.
What I did was get the song recorded in Sonar first, then for the parts of the video where a musician is actually performing, playback the good Sonar recording and play along/sing along or lip-sync with the Sonar while recording the video. As mixmkr said, it is very important to include the audio in the video no matter how bad it sounds - This makes syncing about 500 times easier than if you did not record the sound on the video. Make several takes from different angles and distances so you can have variety in your finished product. When you are finished shooting, import the video into your editor. Many editors can make use of several video tracks. Import the Sonar audio. Sync all the audio by sliding clips. Then go wild cutting and splicing the video, add still photos...maybe some animation.