row level locking on sql server

Hello people,

here is the scenario: We have a message queue and we are processing that queue in multiple threads. Now each thread will take 25 email addresses from a particular table and then process it. So we are looking for a mechanism which actually provides us facility to lock a particular row in the table, once thread has picked it up for processing. We thought about setting a bit manually but select statement on TOP(25) and then update on the same row would be very time consuming in a sense what if another thread comes in  and picks up the thread.

Any suggestions?

Thanks