In the installer for a product I need some sort of license text that basically says "don't copy" - but does this in a 3000 character long legal text ... Where can I find good examples of these to reuse?
I mean all small tools/products out there that are for sales and have these text can't have hired a lawyer - right?
Check out Creative Commons to see if any of their licenses will work for you. I wouldn't recommend copy/modify unless you really understand what you are doing and the text that you are modifying.
Honestly though, if this really is of concern, you should seriously consider hiring an attorney.
How about a picture of Bart Simpson writing on a blackboard:
I must not pirate software.
I must not pirate software.
I must not pirate software.
I must not pirate software.
I must not pirate software.
I must not pirate software.
That's likely to be as good as anything not specifically done for you by your lawyer.
Oh yeah and, when the boys in black from Fox Network (or even Matt Groening himself) come beating at your door for copyright infringement, I've never seen you before :-)
On a more serious note, just install one of those pieces of software and print out its license. Then make sure you understand every clause in it.
Ya know, looking back, I cannot believe I actually typed out those lines above in full without using cut'n'paste. I must be going senile.
Made community wiki, of course, since it's not really that helpful other than to point out you shouldn't rely on legal advice from programmers. I don't ask my lawyer friends about big-O notation.
Companies that sell software typically do afford a lawyer that produces a license text. Such a text will not say "don't copy", since copyright law already prevents users from creating unauthorized copies. Instead, your license needs to say what rights you grant to users.
Companies that don't want to afford a lawyer sometimes google for "EULA" (end-user license agreement), and pick one that they like. Notice that doing so breaks copyright law, since you cannot copy the license text without permission.