If you're eager to develop for Palm's webOS (and the Palm Pre), it looks like you're going to have to wait until the end of the summer...maybe.
Poking around on the Palm developer forums over the weekend, I came across this post from Chuq Von Rospach. In this message to would-be webOS developers, Chuq says, "We’ve been working very hard on the SDK and are eager to open access on a wider scale, but the software and the developer services to support it just aren’t ready yet." The statement continues, saying that Palm will make the SDK "available to everyone by the end of this summer."
For a platform that everyone's supposed to be so hot and bothered about, this comes as a bit of a surprise. If Palm wanted to take on Apple's iPhone, you'd think they would have the SDK in place at launch, rather than two or three months down the road. That said, it did take Apple a few months to get their SDK together and out for developers, but still.