Updating a large database to hash out stored passwords in MS SQL Server 2008

Today I got up and running on an old version/ development version of my companys database, one of the things I discovered while looking through the 'Members' table of the DB is that the passwords are stored in plaintext as opposed to having been hashed and salted. So my question is how do I approach iterating across a large database to convert these plaintext passwords to hashed passwords.Today I got up and running on an old version/ d