In Sql Server, you do not need to specify a value for identity columns (I'm guessing this is what the null in mysql is doing).
So, the short syntax for inserting into your table would be:
Insert Into tbl Values('bla', 'bla')
This works regardless of whether the column is declared to be the primary key of the table and also works for any position of the column in the table. That is, even if the column is in the middle as shown below:
Create Table tbl (
[Col1] [varchar](50) NULL,
[Id] [int] IDENTITY(1,1) NOT NULL,
[Col2] [varchar](50) NULL
)
Sql Server will still quite happily interpret the insert statement and take care of the identity insert.
As other posters have mentioned, in Sql Server you actually need to issue the Set Identity_Insert tbl On
command to be able to specify a value for identity columns.