This appears difficult at first but it's really not. Follow along closely and I'll show how easy it is to make an object appear Metalic.

Step 1: 50% Grey

Whatever your object is..start with a flat fill of 50% grey

Step 2: Selection Samba

1) Using the rectangular Marquee tool Make a "banded" selection horizontally across the object. Hold down shift and creat several more marquee selections of varying size across the object.
2) "feather" the selections by 5 pixels (keyboard shortcut alt+ctrl D ..cmd+opt D for mac users)
3) Open the levels dialog box(ctrl L) and increase the black output slider to about 64. Click ok.
4) with you keyboards arrows. move the selection down about 8 taps and invert it (ctrl+i)

Step 3: Double check

Your object should look something like this now. You can probably get the same effect by holding shift and airbrushing dark bands across the object. It's up to you...just make sure the object is all greyscale and banded like you see here.

Step 4: Bevel it

If you have Photoshop 5 or higher. Add a bevel using layer effects. Once you have created the bevel...make a new blank layer beneath the object and merge the object layer down with the blank layer...this fuses the effect to the object so we can do step 5.

If you are using eyecandy...just make a nice bevel and join us on step 5.

Step 5: Curve it

Here's the magic. With your object layer selected. Open your curves dialog box (keyboard shortcut ctrl+M) and make a curve kinda like you see here. Just click on the diagonal line and drag up and down.

Step 5: Double Check 2

You should now look something like this. Neat eh? but it's still missing a little something.

Step 5: colorize it

Hit Ctrl+U to bring up your hue & saturation dialog box. Click on the "Colorize" box on the lower right and slide hue to about 225 and saturation down to about 15. This will make the metal kind of blueish. You can color it however you want though.

Click OK

Step 6: sharpen it

I know the filter is called "Unsharp" but it does just the opposite. Run the filter with settings similar to what you see here and it will make the darker parts of the chrome "pop" out a bit and lend an air of realism to the whole effect.

Step 7: drop shadow and completion

There ya go! A drop shadow...maybe a few lensflares and you have a cool chrome object and you never had to resort to a 3D application.