We just bought some from pediped. They are supposed to be really good for walking/learning to walk. They arent a hard rubber sole, they're soft but great for outside.
I've heard good things about stride rite too, though I couldnt find a pair big enough for Owen that still had the soft sole. Im sure he will outgrow the pedipeds before long (we are on the largest size soft sole) and we will probably have to switch to the hard soles pretty soon!
Nolan has a few pairs of Robeez and I love them.. they have the flexible rubber soles.. We got them at Stride Rite, but you can order them from the website too!
and the girl's styles are waay cuter than the boys!