I've read places that it's 10, I've read places it's 25 ... which is it?

My predicament is this: I've got proprietary software that runs as a Windows Service, which monitors for files that are uploaded to a shared directory. The files are small (<5kb) so the current limit of 10 connections in XP works fine. We are wanting to combine this with another piece of software, where program updates are pulled from a share on the same PC. These updates reach upwards of 60MB, so the 10 concurrent connections limit could easily be reached. We need a cheap legal way around this (hacking the TCP stack violates the EULA). Server OS's are out because they require a CAL for each device accessing a share.

WINE/VMWare on a *nix box is possible, we are working to "hack" the Windows Service to run under those constraints. But, 25 concurrent connections might be the answer.

What's the limit in Vista? All the EULA says is "(other editions)".

From the Vista EULA you can get from Microsoft (and should have come in the packaging with the copy of Vista you have, btw), under the section (3) entitled "ADDITIONAL LICENSING REQUIREMENTS AND/OR USE RIGHTS":

c. Device Connections. You may allow up to 10 other devices to access the softwareinstalled on the licensed device to use File Services, Print Services, Internet InformationServices and Internet Connection Sharing and Telephony Services.

It's been 10 connections since NT4, and I doubt it'll change anytime soon (if at all, ever).