<p>Visual Studio 2005 doesn't provide an interface for creating relationships between tables in a SQL Server CE database (I'm using version 3.0) and you can't open a Compact Edition DB using Management Studio as far as I know. Any ideas?</p>

Unfortunately there is currently no designer support (unlike for SQL Server 2005) for building relationships between tables in SQL Server CE.  To build relationships you need to use SQL commands such as:
```
```
ALTER TABLE Orders
ADD CONSTRAINT FK_Customer_Order
FOREIGN KEY (CustomerId) REFERENCES Customers(CustomerId)
```
```
If you are doing CE development, i would recomend this FAQ:
EDIT
: In Visual Studio 2008 this is now possible to do in the GUI by right-clicking on your table.