I'm thinking maybe experimenting with different isolation levels may have an effect on a select statement too. In the book I have they talk about what sounds like locking a select statement to prevent dirty reads (when you read data that has been rolled back) for example. Here is a quote:

"READ COMMITTED is the SQL Server Default. At this level, SQL Server will hold locks on data that is modified inside a transaction, but will NOT LOCK data that is selected inside a transaction."

In this case, dirty reads are allowed and select is not locked.

Charlie