Citing "people familiar" with Apple's plans, AppleInsider said the new iMacs got the go-ahead in early September and have been in production for the past couple of weeks.
In addition to a new thinner enclosure, the new iMac line is rumored to possibly include a Blu-ray optical drive. This would mark the first time Apple would include a Blu-ray drive in one of its desktop or portable computers.
Based on previous updates from Apple, it's reasonable to expect the company to also include faster processors, perhaps newer graphics cards, and increased hard drive capacity. Current models feature processors ranging from 2.66GHz Intel Core 2 Duo to 3.06GHz Intel Core 2 Duo.
Hard drive capacities go from 320GB on the low-end model to 1TB on the high end.
Apple also usually keeps the prices of its updated machines pretty close to the previous ones, although they have reduced prices on occasion. Current prices range from $1,199 to $2,199.