According to Business Insider an analyst for Piper has been saying that they expect no iPhone announcement at WWDC, but rather an influx of news on the upcoming Snow Leopard. Analyst Gene Munster was quoted as saying:
"No New iPhones [at Apple’s World Wide Developers Conference]. As indicated in today’s press release, we believe Apple will focus on the new version of Mac OS X, Snow Leopard at WWDC. While some investors may be expecting Apple to launch redesigned iPhones at WWDC, we do not anticipate the launch in early June. Rather, we expect Apple to host a special event in late June or early July to launch a family of iPhones. We continue to expect multiple models, possibly a high-end iPhone with improved specs from the current version and a low-end version with lower capacity and fewer features along with a reduced pricing plan. Such a model could also be used in Apple’s launch of the iPhone into China as soon as the end of summer ‘09."
We can take this with a grain of salt as analysts are not the most accurate in making assumptions on the moves Apple makes. There could be some truth to this, but for now we will just have to wait and see.