more powerful Windows Internet Connection Sharing (ICS) alternatives?

[kz26]

I occasionally need to share my LAN internet connection via an adhoc wireless network from my Windows box, and so far have been using Windows ICS to accomplish this. Obviously, this is a very basic solution and I can't really configure much nor see what's going on. Are there any (free/OSS preferred) that performs the same basic functions as ICS but is also suitable for power users and advanced configuration?

Thanks for any suggestions!