So, now that the iPhone OS 3.0 had been announced, everyone will be wanting to get them. You will need to wait until June. This time frame is to allow developers to check out the new OS and also the compatibility issue (if any) on their existing applications. Link of video after the break.
If you were like me that will not want to wait till June to see how iPhone 3.0 looks like, here is a video link from Engadget on the new OS 3.0.
The OS looks a little slow as compare to the current OS. Anyway, it is too early to say.