Lot of people have already blogged about Oracle Golden Gate so in this blog I will just give pointers to those links.
High level overview of Oracle Golden Gate
http://sai-oracle.blogspot.com/2010/09/what-is-oracle-goldengate.html
Quick overview and demos to setup Golden Gate
http://gavinsoorma.com/2010/02/oracle-goldengate-an-introduction/ (To start with and there are various other tutorials on Gavin’s blog)
Troubleshooting
http://deciphercorp.wordpress.com/2010/08/05/using-oracle-goldengates-logdump-utility/
While testing golden gate I ran into lot of issues and logdump utility helped me a lot to read trail files and fix issues.
Performance & Exception Handler
Extract Internals
http://www.pythian.com/news/7225/oracle-goldengate-extract-internals-part-i/
http://www.pythian.com/news/7459/oracle-goldengate-extract-internals-part-ii/
http://www.pythian.com/news/7617/oracle-goldengate-extract-internals-part-iii/
Oracle Golden Gate by example
Upcoming Golden Gate Books
https://www.packtpub.com/oracle-goldengate-11g-implementers-guide/book
http://apress.com/book/view/9781430235668
Important Metalink notes and Documentation
1194273.1 – How to de normalize data using Golden Gate
1099523.1 – TimesTen replication using Golden Gate