Hi Marius,
I have moved as you suggested core-spring.xml in the META-INF folder of ear, but app context is still loading twice.
Here is piece of Jboss bootstrap log:
...
18:28:55,252 INFO[ NamedXmlApplicationContext] Refreshing org.jboss.spring.factory.NamedXmlApplicationContext@1359c03a: startup date [Thu Jan 27 18:28:55 MSK 2011]; root of context hierarchy
18:28:55,431 INFO[NamedXmlBeanDefinitionReader] Loading XML bean definitions from URL [vfsfile:/D:/views/third-party/jboss/jboss-5.1.0.GA/server/MyProject/deploy/MyProject.ear/META-INF/core-spring.xml]
18:28:55,541 INFO[ DefaultListableBeanFactory] Pre-instantiating singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@37cbcec3: defining beans [core.spring.context]; root of factory hierarchy
...
18:29:00,564 INFO [ TomcatDeployment] deploy, ctxPath=/MyProject
18:29:00,631 INFO [ ContextLoader] Root WebApplicationContext: initialization started
18:29:00,640 INFO [ ClassPathXmlApplicationContext] Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@52bf544c: startup date [Thu Jan 27 18:29:00 MSK 2011]; root of context hierarchy
18:29:00,645 INFO [ XmlBeanDefinitionReader] Loading XML bean definitions from URL [vfsfile:/D:/views/third-party/jboss/jboss-5.1.0.GA/server/MyProject/deploy/MyProject.ear/META-INF/core-spring.xml]
18:29:00,651 INFO [ DefaultListableBeanFactory] Pre-instantiating singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@2e57327: defining beans [core.spring.context]; root of factory hierarchy
18:29:00,653 INFO [VFSClassPathXmlApplicationContext] Refreshing org.jboss.spring.vfs.context.VFSClassPathXmlApplicationContext@10ee0e60: startup date [Thu Jan 27 18:29:00 MSK 2011]; root of context hierarchy
...