Step 1:  Create a blank 200 by 200px document and use the horizontal type tool to create a single letter.  In my case I've used the 'Script MT Bold' font at size 222.  Don't worry if you don't have this particular typeface - just select something with a curvy look (It will show off the effect to its fullest potential).

Step 2:  With the type layer selected, select Layer > Layer Style > Outer Glow from the application menu and duplicate the settings opposite.  Of course, this step is ultimately quite optional, but the dark outline helps the final result show up nicely against the background.

NB.  From this point onwards, if an option isn't displayed in the examples to the left, just leave it at PS default. 

Step 3: Without leaving the layer effects dialog, go to the Bevel and Emboss section and enter these settings.  The gloss contour applied is not included as default with Photoshop, so click on the curve itself and create a duplicate of mine.  Don't get too obsessive trying to produce an exact match - its not that critical.

Optional:  If you want to change the look of your metal, this is one of the main places to do it.  The Depth setting can be varied to sharpen or soften the metal by increasing and decreasing the value.  Likewise, playing around with the gloss contour can help tighten effects around curves, or make them appear softer.   Finally, increasing the size setting can make the metal appear more rounded, but only up to a point - overdo it and you'll lose the metal altogether! 

Step 4: Now progress onto the contour subsection and alter the curve into the one on the left (again, its a custom one not included with Photoshop).  You can try playing around with this setting if you like, but the effects are unpredictable and best left alone.

Step 5: Over bigger interfaces you'll need to add a white colour overlay in the appropriate layer effects section.

Step 6: If you desire a chrome hue, proceed into the satin section and enter these settings.  You can omit this stage if you are aiming for a silver-style effect instead, or play with the curves to aim for different light-sourcing effects.

Step 7: Now press OK to exit the layer effects dialog and admire your work!  Of course, its probably a good idea to add a drop shadow too, and a nice background but I'll leave those bits up to you... ;)

Variations: The layer effects dialog is undoubtedly one of the most powerful features of Photoshop, especially when you need excellent results with minimum effort.  To get the unique dappled effect on the left, all you need to do is go back into the layer effects dialog, find the Texture subsection, and select a texture of your choosing.  Every texture has a slightly different effect, and can have its expression varied with the Depth setting.  Have fun experimenting!  :)