Cable modem here.
Pretty high quality copies of the entire film are available for download at KaZaA.com. The copy most of us have is a roughly 700 MB file that took 9-10 hours overnight to download on cable. It is acceptable quality, good picture quality at full screen, and OK sound. One of us as a slightly better version that is truly DVD quality but is broken into TWO 700 MB files, so it is a bigger ordeal to download that version. Both versions were found at Kazaa. The one I have is no replacement for the DVD that will come out... it is good, but not perfect, and I have to watch it on my computer. So since I will buy the official DVD anyway, and spent more than a fair share on theater tickets, I am able to live free of guilt.
KaZaa is the film version of Napster. You will have to download their software to do it. You are filesharing and getting the file from others that have it available. After downloading it, I think you will want to get KaZaa, and some hidden elements of their software off of your machine, because their software is scary to me. I can get you instructions for all that if you are interested.
If you have newsgroup access, it is also available in the alt.binaries.movies.divx group. I have seen both versions posted there, split into several dozen 14-20MB WinRAR files.