There's several early-version Star Wars scripts over in the movie script section, but I don't believe this is one of them unless it's a different title.  

I discovered this in my family storage locker; a draft, I think sent around to various executives in the 20th Century Fox studio, dated from 1975 or 1976 when Luke was a Starkiller and the Millennium Falcon was just called "pirate ship".  Little did anyone know what kind of an impact this 150 page bonanza would make and forever change the industry.  Let me be clear --- this isn't a good script.  It's 150 pages of "nice try" formatting, long descriptions, incoherent action, wtf moments, and poor dialogue.  If Star Wars was never made and this script was posted in the unproduced section, people would rip it to shreds.

...and yet it's so awesome.  To see that Star Wars, one of the greatest stories ever told in film, came from this...whoa.  

There's been a lot of discussion on the boards recently about how poor formatting can conceal a good story.  Well, this is one of them.  And it's not just the formatting --- it's the overwriting, it's the incoherent descriptions, and it's the painful dialogue.  George Lucas must have had concept art, storyboards and put on one hell of a presentation to get people on board for this because the script doesn't do anyone justice.  Of course, he already had a couple films under his belt at the time so it wasn't like he was unproduced, but still.  

"Blue Leader is gone.  How can they go on?"  Seriously,  you can't make this shit up.

That final space battle where the rebels blow up the Death Star -- 50 pages.  

Granted, chunks of the script are color coded for removal, but if that version were posted on here we'd have another 10000+ view script of people arguing with the author over how bad it is.  That is, if people can even get through the whole thing -- a whopping 150 pages.  I've seen the original Star Wars trilogy about 11 million times so it was interesting to open up this relic of cinematic history.  I'd recommend taking a peek at some of the early drafts that Don has posted; quite an evolution of the story from draft to draft.  

Greg

That's cool that you came across that in your family's storage locker.  I wonder if its worth anything.

I've read bits and pieces of Starkiller and its incredible just how much different the finished product is compared to the early script.  This site gives you the original opening and closing crawl and also gives you the gist of the story.

http://starwars.wikia.com/wiki/Adventures_of_the_Starkiller,_Episode_I:_The_Star_Wars