A few weeks ago there was a question in the microsoft.public.speech_tech newsgroup that amounted to "can anybody recommend a female TTS voice?" There are plenty of possible answers, and mine was along the lines of "there's one in SAPI that you could try, just download it from here: Sp5TTIntXP.exe". (It's installed as part of the SAPI SDK, but this file contains just the voices, without the entire SDK.)
The reply to this was along the lines of "um...thanks...but that's an MSM, so it can't be installed...". (Terminology: MSI = an installable file that unpacks everything, puts it in the right places, registers it, etc; MSM = a module that's merged into an MSI). After I blushed and said "doh!" numerous times I figured "well, how hard could it be to build an MSI?".
The good news is that it's pretty easy. First I tried WiX, which was actually surprisingly easy to learn and has very straight-forward documentation. The only cryptic thing I encountered was that it won't build an MSI unless you've installed the MSI SDK or Visual Studio, but that was pretty easy to trouble-shoot by googling for the error code. If you're comfortable working with XML, give WiX a try.
But I'll be honest, as much as I was liking WiX, I then found out about the "Setup and Deployment" project type in Visual Studio. Wow! This is a no-brainer. It took me about 3 minutes to build an MSI to install the TTS voices. I'm a newbie to setup, so I have no idea what the pros & cons are between WiX and VS. But if you haven't tried using VS to build an MSI, I recommend you take a look. I never actually finished my WiX project - presumably it works fine too, but it requires more skill.
So if you want to give this a try:
I haven't done any thourough testing of the result, so I don't know if there are any glitches. But it seems to work - I can listen to the Mike and Mary voices.
Okay, so you may be about to reply with a comment to the effect of "um, Rob, good for you, I'm glad you've found that VS feature that's been in there for years, but all I really want is an MSI, not a bunch of instructions about how to build one." Yes, I know, I know...