Scott was exactly right. The OUTPUT clause of the UPDATE allows us to get data back from the inserted and deleted tables (the same as we reference in DML triggers). In the case of my code snippet, I always want to process the first record in the table with Status = 1 (Ready to Process) and a StartTime < Now. I contemplated using Transactions and Setting Lock hints, but it was a lot of work compared to using the UPDATE ... OUTPUT statement. This way the record is updated to Status = 2 (In Process) and the row ID value returned to the code in a single statement - no extended or manually coded locking required.
BOL has a good article on the OUTPUT clause; but a couple of points - (1) you can get back any data from the inserted or deleted tables, not just a single column and (2) the INTO table has to pre-exist, hence the CREATE TABLE statement at the top of the code.
The Code snippet is written as part of a loop (using the forbidden GOTO statement - lets see who jumps on that, but that's a different discussion), hence the DELETE statement.
Hope that helps.