Manage Transaction To Avoid Locks

Hi,
I am quite puzzled how SQLServer manages transactions.
Whatever the isolation level I set when performing an insertion, other
connections do not have access to the table in select mode.

Example in SQL Analyzer:
create table foo (
id numeric(10),
data varchar(100)
)

On Connection 1
SET TRANSACTION ISOLATION LEVEL READ COMMITTED
GO
BEGIN TRANSACTION
insert into foo(id,data) values (1,'data');

On Connection 2
SET TRANSACTION ISOLATION LEVEL READ COMMITTED
select * from foo
-> QUERY HANGS

On Connection 1
COMMIT

On Connection 2
Get the result

Using READ COMMITTED level, I was expecting not to lock the table when
performing the select.

Thanks in advance for your help,
Cedric