Hopefully any SQL Server questions will be around SQL and not around managing SQL Server itself (unless youre applying to be a DBA). Things like "what is an outer/inner join" or "what is normalization, have you ever used it, why would you want to" are reasonable. Our interviews are VERY robust and we dont expect anyone to answer every question, but we ask to just to see what level everyone is.
ADO.NET, Id think youd be asked what some of the basic objects are (DataSet, DataTable, DataView, DataReader, etc.), how much youve used them, have you run into any quirks, have you used Expression columns, have you used binding, how have you updated the database (custom SQL, DataAdapter, Command object, etc.).
-Nerseus