I just downloaded OS X Server on an iMac running Mavericks. My macs have no problems seeing the server. Our windows machines (mostly Windows 7) do not. I think they are set up for a domain server on the Windows network. Is there a good guide to help me set up the windows machines?
What is it that you use the iMac running OS X Server for? What services are you hoping to translate to Windows? You can set up a Jabber Server, you can set up a Mail Server as well as a website, but if you're looking for any Mac-specific things like Open Directory or NetBoot, your Windows 7 machines won't really be able to do much with them. This said, if you have a bunch of Windows clients, hosting your own Mail Server in lieu of a proper Microsoft Exchange server is sort of pointless unless your IT department doesn't have the budget for one. Same goes for hosting contacts and calendars.
A Jabber Server could be nifty too, but usually, if you have a business version of Office for Windows, you can just get Lync which is also cross-platform, but also more frequently used.
Long story short, OS X Server has extremely limited use with Windows clients as it is primarily designed for Mac clients. If you want the best of both worlds, what some IT departments like to do is to set up "The Golden Triangle" in which you have the OS X server pull LDAP from the Windows (Active Directory) server to use with Open Directory and just use Open Directory for management of user policies and machines. That way, Macs have all that they need to be as managed as their Windows counterparts.