Photoshop question

I've got Adobe CS3, and I also have some pictures I wish to modify.

How does one go about selecting only one object within a picture to recolor?

Example, one picture is a truck I wish to try different colors upon.

There are many different ways of going about it. My favorite and probably the most quickest and most accurate way is to use the pen tool. It needs to be set on Path.

Basically you draw the shape of the thing you want to be selected. After you finish drawing you convert the path into a selection and from there you can tweak the color under Image -> Adjustments -> Hue/Saturation.

You can also use the polygon lasso tool to do the same thing it just takes a lot of clicks and if you mess up you have to do it over. >_<"

Then there is the magic wand which is kind of random and seems to only work well when the colors are very similar.

sorry bro, not my cup of coffee

As an alternative you could use Colour Range. ( you'll find it in the "Select" menu).

Use the dropper tool to select the colour area you want to select and it'll select it for you. The only problem is it will select all instances of that colour in the image. However if you use Quick Mask, you can deselect those parts you don't want selected.