If the pink line is 4 inches tall, and stretches across the screen, it is safe to say that it didn't just start this way, right? It started off small, and has gradually gotten bigger.
You need to replace the Optic Assembly. If the unit is not under warranty through a third party, you are in luck.
Sony has extended the warranty for this issue through June 30, 2010. You will need to contact Sony's customer relations department (you can get their number from the back of your manual) or their website
They will find you an authorized service provider in your area, help get you set up with an appointment for a technician to come out and assess the problem, diagnose, order parts and install a new Optic Assembly. Free of charge.
Once the new optics block is in, that line will be gone, and you will be back in business.
Now, get on the phone. Seriously.