I thought I'd save all you fellow jucers some of my pain :) and fill-you in on the installation solutions we ended-up using for noatikl and liptikl (both of which are commercial apps built with Juce).
FWIW, I've had the pain in the past of having to write a generic windows-compatible scriptable installer in the past, and am so happy that those days are now behind me. :)
Windows: Inno Setup - free from http://www.jrsoftware.org/isinfo.php
A marvellous tool, really easy to auto-build "standard looking" setup .exe files using scripts. I use cygwin bash shell to grab latest files, build the setup .exe files and zip them up - dead easy. Spread the word!
Mac: PackageBuilder - free from Apple
Builds great looking "Mac Standard" installs, but can't see how to drive it automatically. I use one bash shell script to copy all the bits I need under a build folder, then I run the PackageBuilder manually using pre-prepared configuration file (can't figure-out how to run it from the command line!) (making sure I save the .pkg files into the right folder... that'll catch you out if you're not careful!) and then a second script to build the pkg file into a .dmg file, then zip it up.
Both these tools allow you to embed licenses that the user has to agree to in order to complete the install, which was important to us; in both cases, those text files can come from .rtf files so they're nicely formated!
Right - hoping that helps!