Developer > DBA > Apps 11i DBA > R12 DBA and now you want to become Fusion Apps DBA, then you are on correct page.
Here I shall try to provide some info you should be knowing before you start hands on.
OTN has all the Fusion Apps doc's . Latest version as of today (while writing this blog) is11g Release 1, Update 3 (11.1.4)
It involves lot of Oracle technology such as Database , Identity Management , WebLogic , SOA Suite , Oracle Data Integrator , ApplCore (ATG) , WebCenter , Secure Enterprise Search , Enterprise Content Management , Oracle Forms Recognition & Business Intelligence
Currently supported platforms are Linux x86-64 (64 bit), Oracle Solaris SPARC (64 bit), Oracle Solaris x86-64 (64 bit), IBM AIX on POWER Systems (64 bit), Microsoft Windows x64 (64 bit)\
2 types of Installation types, one bare metal install, other is OVM templates
I think cloning and platform migration is currently not available
So lets start with Fusion Apps