One of the problems with switching to a Mac and still trying to develop against SQL Server is that you end up spending so much time back in VirtualPC. Turns out that there's a great multi-database admin tool native to OSX MacSQL from Runtime Labs let's you do just about anything you need against a SQL Server database (or Oracle or MySQL etc) either on the same machine or anywhere you have a network connection to.
It's still got a little way to go to be perfect but with responsive developers who seem committed to producing a great cross-database management tool it's one to watch.
Currently I do still have to delve back into VirtualPC quite a bit for various reasons (and it's not a painful process - it's responsive and familiar !) but for quick queries or updates to table structures MacSQL is an important part of anyones toolkit.