You don't really need GOOD audio but I see what you mean, when recording guitar videos this is what I do and it helps alot.
Say I wanted to record a video..
Heres what I used to do,
I would plug my geetar in and usually run a wah aswell, and then I would set the Hitachi HD Video camera on the computer desk next to my amp and record the song, but OH GOD I listen to it and it sounds like trash because I can hear my guitar strings and sustainer switch flicking on and off! ugh!. Ruins the whole song.
But Heavens to Betsy I want to record something!
My good chum Al McKenna told me that it would sound better if I did these exact steps..
1. Make sure your amp/pod is near your computer or other recording device.
2. Plug your guitar into your amp/pod and hopelly you have a headphone jack like most amps do.
3. Plug a cable in the headphone jack (if the hole is 1/16th inch then you need a 1/4 to 1/16 adapter to go on your cable.
4. Now the other end of that cable goes to your Line in Jack on you computer (blue hole)
5. Now then, Get a recording program like audacity or Cool Edit Pro 2, which are both free (off limewire
6. Now you can play your guitar and hear it, while recording at the same time.
7. If you have a backtrack to a song for instance (All Alone by Joe satriani) you take you ipod or mp3 player and plug it into a mp3 jack on your amp if you have one.
8. Now you can hear your guitar and backtrack on your computer and now you can record your song.
9. OK NOW set up your camera any angle you want, do worry about having the camera pickup the sound IT DOESNT MATTER.
10. while recording that video make sure your recording program is recording you playing over that backtrack.
11. now! you got your video of you playing the song, and obviously the camera audio quality isnt as good as what is now recorded on your PC.
12. Plug your camera in and import ur little video into your video editing program (Windows movie maker works)
13. you now have your video in there and in the timeline it shows your video track and your audio track FROM THE CAMERA
14. DELETE that audio track, and take the one u recorded on ur computer and import it into collections into movie maker, drag into the timeline (NOT the storyboard)
15. Now u gotta edit it to make sure the video and ur audio are in sync.
PRESTO you now have an alright looking video with good audio.
My fingers are tired from typing all this garble, if you have any questions feel obliged to ask me.