transfer a 2003 sql Web server from workgroup to active directory domain

I need to have our 2003 sql web server join our new active directory. I need to know how to get all the user id’s to work that are listed on the sql web server once I join the domain. Sould I create the accounts in Active Directory before I join the domain? Will the SID’s on the SQL Web server be totally messed up once I do this?

Any help will be grately appreciated.

Sheila