How does one do a redub?

[gfanikf]

I've always wondered how does someone do a redub? What type of software does one use. I have a DVD Burner so I can rip and burn flicks. But I was wondering how does one go about doing it (mixing the materials keeping it in sync). There are a lot of flicks that have a good Raw or Subbed WS print but the englis is only a FS print. I always wanted to try doing this on my on my computer as a hobby. Say take the dub of Taosim Drunkard and redub the crash print and the like.

TIA

I figure this guide may actually be quite useful

www.rifftrax.com/smf/inde...opic=413.0 (http://www.rifftrax.com/smf/index.php?topic=413.0)

I assume it is the general gist?