row_id in sql server....

Hi all,
i have a task that whenever i will write a select query then when the result comes then i should be able to write a column that should write the ROW-ID of these rows. I mean for example i write a select query that gives me the following table:(the query can be like select bill_id,name from myTable order by name)
Bill_id name
25 abc
18 def
26 ghi
23 adfd

but my result should look like:
Row_Id Bill_id name
1 25 abc
2 18 def
3 26 ghi
4 23 adfd

n this Row_Id should be generated automatically...even if when i will write order by name in reverse order then also it should write the row_id as 1,2,3,4 same increasing order...n this automatic function i have to make...i cant understand..if there exist some procedure or function that already does this...or how can i just find the simple ROW_ID in general???
any help will be greatly appreciated.
Regards.create table t(bill_id int, name varchar(10))

insert into t values(25, 'abc')
insert into t values(18, 'def')
insert into t values(26, 'ghi')
insert into t values(23, 'adfg')

select Row_ID=count(*), a1.bill_id, a1.name
from t a1, t a2
where a1.bill_id >= a2.bill_id
group by a1.bill_id, a1.name
order by 1

Row_ID bill_id name
-------
1 18 def
2 23 adfg
3 25 abc
4 26 ghi|||Thanks a lot...it really WORKED...
regards.sql