We are migrating a client's own database schema to our own (both SQL-Server). Most of the mappings from their schema to ours have been indentified and rules been agreed on if the columns don't exactly align (default values etc.)

Previously, depending on who was assigned the task, this has been done either with a mixture of sql scripts or one-off vb apps.

I was thinking there must be a application (commercial or otherwise) where you can assign these mappings/rules and have it stream the data across. Surely the setting up and configuration of this tool would be less than the creation of ad-hoc scripts...

Is there an app? Apart from the obvious 'be careful' any tips to mitigate the stress of a non-DBA porting one schema to another?