Well excessive PageIOLatch indicates that the IO subsystem is been driven harder than it can handle. Whether that's because too much is being asked or because the hardware is inadequate requires further investigation.

CXPacket just indicates that queries are running in parallel. It's a wait a lot of people misinterpret.

Try http://www.simple-talk.com/books/sql-books/troubleshooting-sql-server-a-guide-for-the-accidental-dba/, start with chapter 1.