There are three relatively easy ways to go.
Thumb shifters from a mountain bike (these will work on any kind of handlebar, I just chose to change bars)...
Stem shifters but you still have to take your hands off of the handlebar (sorry, never took a picture of this set-up as I really don't like stem shifters, but I do have a set that I could part with)...
Or, my favorite, Barcons (think there is a set for sale on the For Sale forum right now...
You will also need a down tube cable guide for any of the above suggestions...
