Echoing the voices of praise here 

It has nearly always worked for me (sometimes after updating innounp.exe), but lately I noticed that for some portableapps installers it doesn't work (at least not with the default method).  Has any one had any luck on that front?

XP SP3 with Universal Extractor 1.6.1.

this tool claims to "extract files from any type of archive, whether it's a simple zip file, an installation program, or even a Windows Installer (.msi) package." i think, it will come in handy if anyone wants to just extract files from the installers

btw, happens to be written in AutoIt and acts a front-end for a lot of other cmd-line programs. more info at the website and its forum:

Universal Extractor
Main Window (see attachment in previous post)
Universal Extractor context menu (see attachment in previous post)

That is a really useful post, I can see myself using this product often