From Adept SQL Tools:
AdeptSQL Diff is an intuitive tool to visually compare and synchronize two MS SQL Server databases. The program scans both databases and displays the combined schema tree view, with all differences color-marked. Navigating through the database schema tree, you can see SQL definitions for individual objects (tables, view, stored procedures, etc) compared side-by-side in the larger panel to the right of the schema tree.
You can produce difference scripts for any chosen part or for the whole schema. The schema matching engine generates effective update SQL for any schema difference you need to synchronize, trying to preserve the table data whenever possible.