789:
First -- calm down.
Second -- this is not legitimate.
Now I realize you've responded harshly to other posters who've told you it's fake, but I offer you a different perspective.
I'm an active and donating member of EFF (Electronic Freedom Frontier --
www.eff.com) and I'm directly opposed to every action the RIAA has taken in the last year. There's a similar thread elsewhere in General Discussion of a woman who's finally suing the RIAA for their questionable "bully" tactics. I do not respect them as an organization, and I've not funded their cause by buying an RIAA-endorsed-company CD in years. I myself download songs and occasionally movies, and will continue to do so until the RIAA and the MPAA (their partner in crime) stop dragging their 'customers' into court for nonexistant "lost costs." They've somehow managed to convince the court system thus far that $500,000 is fair price for "stealing" a movie. Not only would stealing a PHYSICAL COPY of the movie be far less than this, you're not (realistically) stealing anything. Because we live in a digital world, things can be given bitwise to another person without every destroying their original. Do I think the RIAA or MPAA should recieve a royalty? Sure.. but not $500,000. They're a very corrupt organization (look at some of the action reports on EFF.com) and are trying their hardest to remove our "fair use rights" which were established long ago. During the age of the casette tape and the VHS similar organizations tried to stop their progress because they were afraid to update their liscensing scheme. (Basically, I'm on YOUR side).
^^ To the would-be flamers, I realize that you can feel differently than I do above, but I would apprecite you not derailing it by attacking my opinion. I only offered this as an explanation for 789.
Look very carefully at ALL the documents you've recieved. Although I have an extreme distate for the RIAA, they're usually very official in their dealings with the "criminals" trading their movies or songs. There are PLENTY of hoaxes out there, posing as the RIAA or MPAA, designed by organizations who support their causes. They could simply choose an IP or physical address at random and send you a form letter like the one you've gotten. Likewise, pranksters seem to be enjoying a similar process, as I just got an "RIAA warning letter" via email. A trace of the headers shows it wasn't anyone remotely associated with them and was in fact just a student at our University.
Soo --- a long story short -- unless you get something OFFICIAL, take this "litigation warning" with a large grain of salt. I'm not implying that you've made it up or that the documents you've recieved don't SEEM official, but I'd be willing to bet with near 90% certainty that you have nothing to be worried about in the near future.