http://schwalbetires.com/node/200/ok

Go to this link, and you can order them in 650 x 23 from schwalbe direct. Their shipping is very reasonable too, since the tires fold compactly. The reason I tried them is that I have a terry with a 700cc rear/ 24" front tire, and there is also not much choice in 24" tires. They recently introduced this tire in 24" and I have been so impressed. I have yet to get a flat with them! It is remarkable given that they are also light weight and handle well. The center is very firm, it is their special flat resistant compound, not kevlar, but in my experience works even better.