1. it will release in August or September this year. 2. the case will be metal. 3. will be slimer. (combine 2 and 3, i guess it will look like Apple display) 4. It will use Santa rosa chips. spec similier to Macbook Pro.
Although i don't know when the iMac will be available, it is a good idea to at least wait for Leopard. (Steve said in August)