Copy table data between tow databases using sql server 2005

Question

i have one table 'user' in database 'mainUser2011'  the table is bellow

userId        Username
---------------------
1                Asok
2                kishan

userId       :- is autoincrement(Identity is on) and primary key
Username  :- is nvarchar(50)

and the same table 'user' in database mainUser2010

i want to copy the contenet of database in mainUser2011 to database mainUser2010 the curesponding table