The OWB to ODI 12c migration utility provides an easy to use on-ramp to Oracle's strategic data integration tool. The utility was designed and built by the same development group that produced OWB and ODI.
Here's a screenshot from the recording below showing a project in OWB and what it looks like in ODI 12c;
There is a useful webcast that you can play and watch the migration utility in action. It takes an OWB implementation and uses the migration utility to move into ODI 12c.
http://oracleconferencing.webex.com/oracleconferencing/ldr.php?RCID=df8729e0c7628dde638847d9511f6b46
It's worth having a read of the following OTN article from Stewart Bryson which gives an overview of the capabilities and options OWB customers have moving forward.
http://www.oracle.com/technetwork/articles/datawarehouse/bryson-owb-to-odi-2130001.html
Check it out and see what you think!