Open Table in SQL Server 2005 is replaced by “Edit Top 200 Rows” in SQL Server 2008. You can change that command in the Tools > Options > SQL Server Object Explorer > Commands.

But once you right-click a table, choose “Edit Top 200 Rows”, hunt on the toolbar for a button called “Show SQL Pane”. From here you can edit the query so the grid shows a subset of the data that you want.

The reason for this change is because people were accidentally opening huge tables with the old Open Table command.