The absence of multi-tasking on the iPad, despite the "blindingly fast" processor, is causing a lot of comment. Could it be that Apple have deliberately not mentioned multi-tasking because they do not want to spoil the launch of the iPhone 4G? This would explain a lot and could even enable multi-tasking to be added as part of an OS update before or soon after the product hits the shelves.
The update to the iPhone, the so-called iPhone 4G, has been tipped for mid-year. This next iteration will almost certainly include a much faster processor and a greater feature set. Multi-tasking has been requested for so long, and there is now clear MT competition from the likes of Android, that it is almost a given that it will appear on the next iPhone. For iPhone, read iPad.
If Apple had hinted at multi-tasking as part of an imminent OS upgrade they would have partly spoiled the milestone iPhone announcement. So I believe that we will see enhanced capabilities for the iPad almost before it is available.
Another reason for the launch reticence, of course, could be the issue of battery life. Multi-tasking will seriously deplete battery life and it could be that Apple wished to get the launch out of the way on the back of the promised ten-hour range. If the enhancement comes in a few months everyone will still have a ten-hour battery life in their minds.