If you want to see an impressive Website introduction, look no further than the Third Wisconsin Volunteer Infantry site. It'll wow you from the get-go.
Although it's a visually stunning site - I consider it on par with my favorite, Syke's Regulars - bear in mind that it's new and a work in progress. I found the navigation to be a little confusing. The site that I linked here is apparently a portal to other aspects of the site. If you look on the left under "Directory", you'll see "Living History Site", and that's where you need to navigate to for the reenacting stuff.
The reenacting portion has a good amount of information, plus a few sutlers I haven't heard about. The navigation is still a bit tricky, but don't let that stop you in enjoying a great site.
Update: Use this link to navigate to the 3rd WI's related groups.