what are the best useful software?

AVS video editor.

Virtual dj is best.

Once you get the video in wmv you should be able to use ffmpeg to convert it to whatever you like. Otherwise there are options like kdenlive or pitivi for video editing.

Virtual dj does have some neat options, i like how you can spin the disk around to go back/forward/scratch the song, loop by x beats per second and then there's the great beat sync button. Haven't seen that functionality in other programs, but there are editors like audacity, which you could crop out the selection you like and paste it over and over again, not quite the same but the manual way of doing it.

for video edit, i m using a software whch came with my canon digital camera.this is the best i hav ever found.

For audio, sonic foundary sound forge may be better.

in windows seven dvd maker is best now try fruity loop for your song