thread pooling

i have a table. who have always new record on it
so i want to process all record when i process it i change the status of record field to begin processing and when i finish i update the status to done
i have read some topics and they talk about thread and time.. and pooling

the default value of status of task is "to process"
do a task ! like select top (100) from table where status = "to process"
than i update the status to begin process .
insert in other table
update status to done
i want to use transction begin and end and rollback if my job not committed it will be rollback  i don\t know about how to it on c# and mssql ..


than sleep to 30 second.. after fetch all top 100 row and do my job slelect update insert

than i repeat it always. i want to run it as windows services.

can any one check tthis code and tell me if it was i try to doo

http://www.codeproject.com/Articles/16615/How-to-Create-a-Simple-Polling-Service

  Private Sub PollProcess()
        ' Loops, until killed by OnStop.

        EventLog1.WriteEntry("PollingService service polling thread started.")
        Do
            ' Wait...

            System.Threading.Thread.Sleep(30000) ' 30000 = 30 seconds


            PollingPass()
        Loop
    End Sub

    Private Sub PollingPass()
        Try
            ' Do Stuff Here...

            EventLog1.WriteEntry("PollingService service polling pass executed.")
        Catch ex As System.Exception
            EventLog1.WriteEntry("PollingService encountered an error '" & _
                ex.Message & "'", EventLogEntryType.Error)
            EventLog1.WriteEntry("PollingService service Stack Trace: " & _
                ex.StackTrace, EventLogEntryType.Error)
        End Try
    End Sub






            ' Do Stuff Here...
here i wil but my sql query????


and i want some one tell me if this app  do a a stuff when the stuff finish ... sleep 30 second and repeat the same jobbbbbbbbbbb???????????/

i need to do like this ?