The Scuba Trust is a group I've bumped into a few times on dives around the place. They are a charity who ensure that disabled people can go diving, safely.
See http://scubatrust.org.uk/ for their site. Check out the videos in Barbados in the Video section (can't link as it's flash). They use a wheelchair with bubble tyres to get them in the water, then people help them into the boat. You'll see they are wearing a yellow harness ... makes it much easier to pull people in and out of boats. Police and some other recreational divers wear a harness as part of their normal kit, so they can be grabbed easily and winched / pulled up things. It's not just for disabled divers.
Disabled divers are accompanied by a couple of able bodied divers. I've seen them using fins that fit over their hands if they cant use their legs. They can also use a mono-fin on their legs if one leg works whilst the other doesn't. They use all sorts of adaptions to allow the disabled diver to dive as independantly as possible.
Great organisation. They are always laughing and joking, whenever I've seen them. They must all really enjoy it - able bodied as well as disabled.
||It's performance art|