It was really just a matter of time before this happened, but this seems like the most official thing we've seen to show that Sony and Ericsson really are no longer Sony Ericsson anymore after Sony bought out Ericsson. The buyout was completed just about a week ago and Sony is already moving on to promote its new solo venture.
So, as of today, if you try to go to SonyEricsson.com, you will be automatically forwarded to the SonyMobile.com website. The site looks right at home in the Sony family of websites and should have all of the info that you would expect/want. Word has it that Sony is also planning to retire the @SonyEricsson Twitter handle in favor of @SonyXperia, but as yet @SonyXperia is still just an egg.