Dr Patrick McCarthy's book Relax and the accompanying hypnotism MP3 has been very useful for learning optimism.
Track 3 Turning Pessimism into Optimism covers the basics of Learned Optimism and the 3 Ps - when something unwanted happens a pessimistic way of thinking about it is that is was Personal (created by me) Permanent (it always happens) and Pervasive (happens in every situation).
To move over to an Optimistic way of thinking about an unwanted event we need to think that it was caused by someone / something else (not us), that it was a temporary event in time, and that it was caused by a specific set of unusual circumstances.
His example was someone hanging out washing and dropping pegs - the pessimistic view "sigh, I (personal) am always (permanent) dropping things (persistent across all sorts of things)", then the optimistic view "these cheap plastic pegs sometimes slip" (not personal, sometimes not permanent, only plastic pegs, not persistent).
For wanted events the opposite is needed - so when something good happens the optimist thinks that it was because of what they did (personal), that good things are always happening (permanent), and that good things happen in all areas of their life (persistent).
So now I am carefully monitoring my thoughts and re-framing them as required to learn optimism
In "Track 2 The Glasgow Bouncer" he talks about how to displace uncomfortable thoughts with better ones. He says that each part of our brain can only think one thing at a time, so if what we are focusing on is distressing then we simply need to replace the thought with a better one (let the bouncer through the useless thought out). He has you link 5 past positive experiences, such as when you felt totally loved, to the fingers on one hand, and 5 great future imaginations to the fingers on the other hand. Then when you detect a negative thought in one of these areas you are supposed to touch the finger to generate the replacement. So far I am taking a simpler approach detecting non-useful thoughts replacing them with useful ones.
"Future books are planned for release in 2013 including how to combat Insomnia and Irritable Bowel Syndrome, how to make childbirth more comfortable and how to help treat infertility."
http://www.huia.co.nz/?pg=107&authorid=343