Shining Effect

[Coyotemax]

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..

[Ascension]

Airbrushing, blend modes, gradients, or opacity tweaks is what I would use. I do just about zero photo work, though...very rarely on stuff for my sis and nieces.

[mearrin69]

Yeah, lens flare plug-in should get you most of the way there. A large, soft paintbrush with low opacity would let you do it by hand as well. For the rainbow effect I'd use a gradient and opacity/blend modes.
M