UPDATE (12/23/2007): There’s a nice quick summary of how a mobile device can be used for in a home environment
HERE, in the first post of the thread. It’s worth a read if you still don't really understand what UPnP can be used for in everyday life. (Note that it discusses the
Nokia N95 in this scenario. Of course, any other, UPnP- & remote control-capable mobile device can be utilized in exactly the same way. Also note that it still discusses the old, pre-v20 firmware of the Nokia N95. As has also been mentioned in the (currently) last post of the thread, the N95 has received real renderer capabilities in the meantime.)