Resigning would have meant new elections for President within 60 days (as the Egyptian constitution requires). By transferring his powers to Suleiman, Mubarak allows for a reasonable consideration of constitutional amendments. From now, it is Suleiman's problem to go with some openness through this process. So far he has not given details of the amendments he was considering. That should change, and the people should demand it. It will be reasonable even for the US to ask for the details. But let neither the public nor the US demand Mubarak's resignation. It will be bad for all.
4 UN peacekeepers injured in Sinai and taken to hospital in south Israel (Haaretz)
from the article: Mubarak hands over power to Egypt VP, but won't step down