The first "steampunk" stuff I tried was work that had been published by Jake von Slatt on his site, SteampunkWorkshop.com, and referenced heavily from Green Art, a French metal etching artist.

Briefly, it involves printing an image with a laser printer onto inkjet photoglossy paper.  This creates an image out of toner on the glossy paper, but because it's glossy, the image doesn't adhere 100% - it can be transferred to metal by pressing the toner image against the metal and ironing the back of the glossy paper.  This "melts" the toner onto the metal, and acts as a protective mask for the areas you -don't- want etched.  Then you hook up the metal piece to one end of a batter (or in my case a computer power supply), hook another electrode up to the other terminal, immerse the pair in a solution of copper sulfate (i.e. water + Root Kill), and allow the electric current to pull ions off your workpiece and onto the electrode.

I've blogged more about this the first time I tried this, last year, on my EmbeddedRelated.com blog.

In the figure below, the top piece represents the first attempt of my most recent endeavors.  You can still see the black toner "mask" around the edges of the "Steampunk Laboratory" text, which I didn't finish sanding off after etching.  I didn't finish it, because I forgot to protect the edges of the brass workpiece with electrical tape before I etched it.  As a result, the solution etched not just the exposed words "Steampunk Laboratory", but also all of the exposed metal around the edges.  Oops.

The middle piece represents my second recent attempt.  This time I -did- protect the other exposed areas with electrical tape, and even though I was checking the etching depth every 15 minutes or so, I didn't catch it before it etched all the way through a couple of places - the "S" and the "O"...

The bottom piece represents the third attempt.  This time I checked more regularly, and pulled it out a few minutes short of the previous etching time.  It's getting better - I think the bottleneck in the resolution is the quality of the laser printer I'm using now.  (I bought it used at a flea market for $25, and it's quite old, dusty, and dirty).  The bottom of the "L" and the "B" didn't quite print right (I covered the errors with pieces of electrical tape, the outline of which you can clearly see). 

Since I'm fairly confident that the etching process itself is working pretty well, I went ahead and sought out a cheap but newer laser printer on Craigslist.  Bought one new-in-box for $60 from a guy who bought it but never opened it before he decided a color one.  I myself haven't tried it yet, but that's on the list of things to do this week!  Hopefully with that printer I'll be able to produce satisfactorily high resolution etchings and galvanic machinings.  Should be fun....