None of that info has been announced. There have been constant rumors of delays and I don't even think the Japanese launch date has been totally nailed down. Sony may end up holding it in the US for next holiday season to take some wind out of the Xbox 2 launch.
As for prices- again nothing has been announced. Speculation has placed it at $300-350 but that's based on the Japanese market which has shown a willingness to play more money for such things than the Western market. I think Sony is waiting to see how well the DS is received and how well the PSP does in focus testing before setting a price. They may end up having to price it at $250 here just to make it viable and eat some of the money on each unit sold the way MS does with Xbox.
It's true. So far everything is just speculation. However IIRC Sony has said that they want to price the PSP so they will be able to make a profit off the hardware and not lose money like the main consoles do. Also isn't the disc format they are using proprietary as well? If so that further increases costs in the short term until manufacturing is streamlined. Ah looks like it is (pulled from IGN
The PSP uses a proprietary Sony disc called the UMD, or Universal Media Disc. Capable of storing up to 1.8GB of data (a CD holds 0.650GB, a DVD holds 4.7GB), the UMD is a disc format enclosed in a small cartridge (similar to the Sony Mini-Disc format.)
No, the UMD cannot be written to. Only Sony will be able to create UMD media -- the company has no plans to make external UMD writers devices, and even third-party publishers will not be able to create their own discs without Sony's ability to press the data to UMD.
So if Sony is going to be the lone manufacturer of the discs they alone would be the bottleneck.