I've been searching for a solution to this and have not found anything definitive yet.
We run a TFTP server on a Linux host and can PXE boot systems to a menu system we have constructed for it. What we want to be able to do is add an additional menu item to the PXE menu configuration file on the Linux server, so that our Windows admins can PXE boot systems and have them directed over to a WDS server that is running on a Windows 2008 server.
So far all I've found are lots of examples on how to use WDS to deploy Linux systems, here for example.
But there seems to be nothing out there on how to use WDS through a pxelinux menu that's sitting on a Linux TFTP server. I've seen some references to using pxechain.com, but not many details about it, and so far my experiments have not yielded any success.
Is anyone doing this? If so do you have a working example config you can share?
I've kind of got a solution. Using the link above I created a PXE menu on the WDS server. Our DHCP is configured to initially send PXE requests to the WDS server where the menu gives them a choice to boot Windows or Linux. Windows just boots into the WinPE WDS stuff. The Linux menu uses an iPXE compiled file to reset the PXE and send the requests off to a Linux webserver where all our Linux builds live.
It's a little cludgy, but it seems to work ok.