When I started this lottie-lark a few weeks back, I started complaining to others about my newly-acquired sandpaper hands. Someone really nice (Trixiebelle :) ) sent me a bar of soap which has done loads to eliminate this - after I've finished gardening I wash my hands using it, and it makes a huge difference.
It's called Seven Wives Gardeners & Workshop soap. It contains essential oils, olive oil to moisturise, and an exfoliant.
Thoroughly recommended.