The plan is to install an internal-gear hub in place of the worn out damaged standard gear system on there now. I've been really impressed with internally geared hubs in every bike I've tried. So far, on my Fly-By, I've used gears 1-6. I can see going to 8 very very rarely.
I've allready ordered a Shimano Nexus Inter-8 hub. That's the most expensive part. I'm going to try my hand at wheel building with it, and I hope to use the existing rim. We'll see. So I still need: spokes, shifter, crankset, chain. Should be a fun project!