Download the Visual Studio add-in for SQL Server Compact 3.5 and 4.0 from here

A blog post describing the new features is available here

New in version 2.2:
- Menu option to generate an Windows Phone DataContext (.cs) in the current project (in beta)
- Menu option to add Description to tables and columns
- Descriptions or name shown as Tooltip on tables and columns
- Improvements to Db Diff script
- Options dialog for saving options from session to session
- New options available via new Options dialog:
* Include DROP in Db Diff script
* Display query results in DataGrid (SQL editor)
* Display binary result as a hex string (SQL editor)
* Show Descriptions Table in Treeview
- Save script (SQL editor)

Fixes in 2.2.0.3:
- Execution of multiple statements with GO was broken

Fixes:
- Keyboard mappings in editor were broken
- Editor made more "text-only"
- Fixed some user reported exceptions
- Proper sorting of multi-column primary keys
- SELECTs against INFORMATION_SCHEMA views now work