This new feature is not mentioned anywhere, but listed in the docs:
sp_rename: Changes the name of a user table in the current database. Currently, sp_rename support in SQL Server Compact 3.5 is limited to tables.
sp_rename [ @objname = ] 'object_name' , [ @newname = ] 'new_name' [ , [ @objtype = ] 'object_type' ]
In the following example I will demonstrate it's use (using the VS 2008 beta 2 Server Explorer):
But runs the query none the less.
Do a refresh...
And voila... all from plain old T-SQL!