Then use windows movie maker(inside your windows machine) to add them to video

u need to convret the video to wav or wma, mp3 audio, then imported to windows movie maker.

I Use E.M. Youtube video download tool.

It works great and easy to use.

It can download video from youtube , myspace, veoh, yahoo or any other video websites autoamtically.

http://www.effectmatrix.com/Youtube_vide...

It can also convert flv video to any audio include MP3, wma,wav,ac3,mmf,amr,ogg,aac..., to any video formats include 3gp,avi,wmv, mpg,mpg4,asf,swf,h264,mov,jpg, that can be support by PSP,iPod,iPhone,Apple TV video,iTune,MP3,MP4,Zune,Cellphone,Digit... camera,DV,CD/DVD/VCD/SVCD.
quite a lot of samples tunes on utube.. do a search at youtube

this will help you...Use 'zillatube'.

It is very easy to download videos, and it downloads fast too..

Then you can convert youtube videos into the music mp3 music (and other formats too) with zillatube. This is the fastest way.

Then use windows movie maker(inside your windows machine) to add them to video.

It works very well - to get ZillaTube, click the link below, and select the first search result for download...