If you want to watch the Royal Wedding on Friday but won't be near a TV, Livestream is serving up several choices for live streaming. They have a special page setup with links to live coverage from the Associated Press, ET The Insider.com, the UK Press Association and CBS News. All four channels are already loaded with lots of archive videos and recent coverage so you can get up to speed on all the Royal players before the big day.
Livestream has apps for iPhone and iPad that should allow you to watch the wedding on your mobile device. Each channel has to choose to stream mobile compatible video, however, and I couldn't find any information indicating which ones would be streaming to mobile. I would be shocked if they didn't do it though, because they know their numbers will be larger if they do.
Don't forget there are several excellent Royal Wedding iOS apps available too, and they can provide you with a lot of up-to-date information without using as much data so you can save your data use for the royal nuptials.