I think that question can't be answered without knowing more of the application. I suggest you throw the deployment at AS7 and see what happens and pick off the errors one by one.
As far as a migration guide specific to WebSphere to JBoss migrations I am not aware of any. The basic steps will be:
1) port over the server side resources.
2) create jboss deployment descriptors.
3) install the application
4) resolve anything that does not conform to or violates the JEE spec. In other words pick off the errors one by one as Nicklas suggests.
I have done many WebSphere migrations to JBoss while working in the financial industry. I have solved many of the problems related to apps using WebSphere specific API's (aka vendor lock in). Feel free to send me private emails with any problems you run into and I will do my best to answer them.
I created a couple of community pages to capture information about migration from WebSphere and WebLogic to JBoss. If you can provide any information, feel free to add content to those pages. The links are here:
If you prefer not to add content directly to the wiki, please send me any notes you have and I'll be happy to add them myself.
Can anyone let me know wht is the equivalent of server.xml in Jboss .
More over How do i download the Jboss MAT tool . I am not able to download it. Pls help me
Thanks in Advance
sgilda - Great to see those docs materializing:) I will add content when time permits.
Arun - There is no one to one mapping to the server.xml. Most likely you will use one of the <JBOSS>/standalone/configuration/standalone*xml files. The standalone xml files are for a single JBoss instance and will have server.xml equivalents and more. If you need to replicate a WebSphere cell topology then you want to use the <JBOSS>/domain/configuration/domain.xml and host.xml. In a jboss domain (aka websphere cell) the domain.xml will have the server.xml equivalents.