A latte steamers can cost hundreds of dollars espresso machines are much cheaper. I bought this one at a clearance sale for $15 and the conversion cost almost nothing.
Step 1: Plug the Coffee Steamer Port
Disassemble the housing and remove the coffee steamer attachment. I won't get into specific sizes because different brands will vary. You will have to drill and tap the coffee steamer attachment port and plug it with a set screw. (use pipe tape or sealer on this) Disconnect the steam wand hose it will be connected to copper tubing later.
Step 2: Make the Steamer Hose
You will need a piece of 1/4 " O.D. copper tubing the length depends on the design of your machine. I made an aluminum block to hold the pipe and bolted it to the side of my machine. I covered the pipe with some old BX wire cable that I removed the wires from. This made things look better.One end of the tubing fits onto the wand hose that you removed the other end has a copper pipe compression fitting installed. You need to attach the steamer head from the original wand that I am sure was too short and low to put a regular size cup underneath anyway. I drilled and taped the steamer head on my unit to a 1/4 - 20 thread and then made up a fitting to attach to the compression fitting that I had installed.(See nozzle adaptor in photo)
Step 3: It Is Ready to Try
Pictured above is a glass with cold milk in it and the same glass after 15 seconds of steaming. Look at the foam this is what you want on top of your latte. The only drawback to this unit is the small steam chamber, it works fine to heat and steam one drink but then you need to wait for more steam to develop. You can overcome this by microwaving your latte first to heat it up a little then use the steamer to generate the foam. I use my unit every day to foam my homemade chai latte's.