IR is no longer used. I don't see any need for it. And WP probably supports IR, but nobody makes phones with a IR transmitter/reciever.
Also, soon TVs will also have voice commands (if not already) so remotes will be preety useless.
IR is no longer used? Where do you get your info ? Everything still uses IR, cable boxes, Dish boxes (some are selectable to use IR or RF), new TVs, even the Xbox has a IR jack on it.
If you want to see if a remote is using IR (this is great for checking if the batteries are good too), Take your phone, enable the camera, Point the remote at the back of your phone, look at your phone, push a button on the remote, if you see a light blinking, then it's a IR remote.
The phones with a IR blaster on it have PLENTY of Apps to use your phone as a remote. I used to have this on Windows Mobile with a cool app, I would go to a bar, sit across the room and change the channels on the TV with my PDA/Phone. It's great even just for that....
And Personally, I would rather hit a button on a remote than trying to change channels with my voice...I would find it a lot easier to use...maybe it's just me..