Adobe Photoshop is the perfect 2-D image editing program; however, though limited, you can do some 3-D effects or actions in Photoshop.
First there is the Filter: Render: 3-D Transform (in Photoshop 7). This will allow you to create simple 3 dimensional shapes or wrap an image in a 3D shape. There are three kinds of 'primitives': sphere, cube and cylinder. Using 3D transform will simply distort the pixels and you may have to add a drop shadow to see the effect.
In the 3D transform editing box are your primitive tools to create basic shapes and also basic editing tools; Select and Direct Select. Select moves the entire object and direct select allows you to drag the anchor points to make adjustments. You have viewing options such as the pan camera and trackball. These allow you to preview and move the 3-D render around from different angles.
Remember that whatever filter you run (such as 3D transform) is going to apply to the layer that you are currently on. If you wanted to create some 3-D shapes, first create a new layer and fill it with a color. Then you'll still have to create some drop shadows or darker shades of color fills on the 3-D shapes layer.
The rest of your options come down to the Edit: Transform function. Here you can create some 3-D effects with text really well. All you have to do is use the different transform functions. It's easiest just to free transform by using shortcuts: Alt (Opt) E: F (Edit: Free Transform) and then holding down the Ctrl (Cmd) key while you drag any of the 'handles' in any direction you want.
If you are going to add filters or layer effects with a 3-D transform you're going to want to rasterize your text layer first. Right click on the layer in the layers palette and choose 'rasterize layer'. This will convert your text into a normal 'layer' which you can then do anything you want to it (as with normal layers vs. text layers). After rasterization, you can't edit the text again so make sure to make a backup copy or be ready to retype your text with the text tool. Here is an example of a "3-D" transform.
3-D effects with Photoshop
The 3-D options are hardly anything compared to Alias Maya or other 3-D programs, but then again, Photoshop isn't meant to be. We should be grateful there are some 3-D effect options available. With all of the file format options you can import and export 3-D files created in other programs for further image editing in Photoshop and you can still do some nice 3-D perspective transformations on your layers.