Two different topics here:
1 – you will need routers that support multicast (in other words you can specify multicast addresses). You can use an untangle router (linux build it yourself) with mroute added if you don’t want to buy any of these.
You will also probably want to implement ipv6 on your network, since it supports multicast much more efficiently.
As well, certain protocols offer better support. Check here:
2 – on the wireless side you’ll want to pay close attention to the DTIM and beacon settings (faster/more often) and power saving options (like turn it off). This is true on the router/access points and on the clients.
One other excellent resource I found was:
Hope this helps.