SQL Server Database Compare Tool

I don't know about a free SQL Server database comparison tool, but here's a good one which does the job great and is worth buying.

RedGate Software - SQL Compare

It seems that SQL Delta might do it.

SQL Database Compare and Synchronization And its free download: Download SQL Delta 3.0

Besides, I can tell no more as I have never used it.

Another SO question's answer on the topic might help as well.

Anyone know of any good Database Diff tools?

The accepted answer by Scott and the Dev Team seems to be pretty complete.

You own the free tool already.

Do you really want to trust your database and your job to something someone is giving away?

You can make this with Database Workbench

Easy migration and management With our Schema Migration and Schema Compare tools you can easily migrate legacy structures to your new database engine. You can even migrate ODBC or ADO data sources to your new databases! This can give you a head-start when converting an old product. By using the Schema Compare, you can easily create a change-script from your newer database to run against older databases

You can also investigate TMS Data Modeler

Compare models between versions or between projects A full comparer is available for you to check the differences between two models. You can perform comparison between two versions, or even between two projects. The comparer provides a very friendly visual interface that shows the differences in a tree view and also in a SQL diff format. From the comparer you can choose which items you want to update to generate an Alter SQL script.

This 2 tools are not free

Data Compare, Test Data Generation, Documentation Creator...7 Tools in total www.sqldog.com