I believe those are referred to as lens flares.

Photoshop has a few basic ones built in, but there are a few plugin filters that make nice ones. One of the Kai's Powertool plugins has a very configurable (and highly recommended) filter for that, but last I checked it would cost a bit of money.

Unfortunately I don't have a lot of time right now to do a comprehensive search to give a list, but http://www.google.com/search?q=lens+...ugin+photoshop will give you a good start..