I just created my first test application with Grails 2.0RC1 and used SQL Server 2008 as the database.
Here are the quick steps:
1. Install JDK/JRE (I used 1.6.latest)
2. Unzip Grails 2.0RC1 to an C:\grails2rc1\ directory
3. Create environment variables for JAVA_HOME(point to jdk install)
4. Create environment variables for GRAILS_HOME(point to grails directory)
5. Add the following to PATH environment variable: ";%JAVA_HOME%\bin;%GRAILS_HOME%\bin"
6. Test that you can call "javac" and "grails --help" from C:\
7. Create a database for grails from Management Studio
8. Create a user/pass and give it access to this database(I usually give it dbo and sysadmin during the initial install phase. You should dial it back after that)
9. ** TRICK ** Make sure TCP/IP is ENABLED using SQL Server Configuration Manager, under SQL Server Network Configuration -> Protocols for MSSQLSERVER
10. Create a directory for your app (C:\work\apps)
11. Open a command prompt and "cd" to that directory
12. "grails create-app myapp" (This creates the Grails structure)
13. Download the latest jTDS Driver and extract the files to a temp directory
14. Copy the jtds-1.2.x.jar file to the directory C:\mayapp\lib
15. Your conf/DataSource.groovy should look something like this:
pooled = true
driverClassName = "net.sourceforge.jtds.jdbc.Driver"
dialect = "org.hibernate.dialect.SQLServerDialect"
... other stuff
dbCreate = "create-drop" // one of 'create', 'create-drop', 'update', 'validate', ''
url = "jdbc:jtds:sqlserver://127.0.0.1:1433;databaseName=grails2rc1"
username = "grailsadmin"
password = "your-Pass123"
16. Create your 1st controller: "grails create-controller dashboard"
17. Save, then run "grails run-app"