I have seen similar instructions selling on eBay for $4.99 on Buy-It-Now (here and here), but I question the legality of selling this information for any price. First of all, the modification is easy to figure out for any lay person with a nearby RadioShack. Second, it is illegal in most jurisdictions to bypass the video cut-off of an in-dash DVD player so that the driver can watch DVDs while driving, though experience tells me that there are some out there stupid enough to want to do just that.
Because I am an ethical darwinist, I will tell you how to perform this hack and I won't charge you a dime. If your IQ is such that you feel it is safe to drive while watching a movie, just make sure not to take anyone else out with you. But for passengers in the front seat, there is only one way to enable them to be entertained by watching their favorite movies on long road trips. Here is how to do it.