The Xoom has no inbuilt DLNA streaming. But there are apps that can handle it.
I use the free app
upnplayer/ to stream media from my nas. The nas has a DLNA-compliant media server. I tried a lot of other apps on the Xoom, but most failed. Upnplayer is a little rough, but actually works. Any info about other working (on Honeycomb) upnp-apps are welcome.