Plz tell me how to handle distributed transactions between more than one databases using hibernate.. Does hibernate support this feature and how can we handle all this..

Thanks in advance..

Use a dataasource with XA transactions (eg. in JBoss).
It should 'just work' if you also use the transaction manager of your container.

I've configured multiple datasources in Application Server say 'JBoss'. Then how can we configure/use all these datasources in a [b]SINGLE[/b] hibernate configuration file, so that when we obtain a session factory based on that single configuration file, it could be used to execute distributed transaction across all configured datasources...

Thanks in advance..

You need a configuration per datasource.
This will give you 2 sessionfactories. It is not possible (as far as I know) to use 2 datasources in 1 hibernate config. (And perform queries that operate at both databases at the same time).