Apple is said to be refreshing its entire iMac line sometime in the next four weeks, following the release of its “unibody” MacBooks. Sources close to Apple indicate that some of the parts built inside Apple's latest notebooks will be making their way into revamped iMac models as well.

AppleInsider cites people familiar with the company's plans as saying that “changes to the iMac family will largely consist of performance improvements and technology refreshes,” the report reads. The source also points out to the architectural resemblance to the MacBook lines, as a potential hint.

Parts undergoing changes / replacement inside the revamped iMacs include the processor, the connectivity ports and (maybe) the graphics solution, the same people say. However, the iMac already has a 1066MHz front-side bus, so not everyone is putting all their money on a processor upgrade. However, with Snow Leopard on the way (Grand Central technology), Apple's Macs will have to boast an increased number of processor cores.

As for the new connectivity, iMacs are most likely getting the DisplayPort now found on Apple's aluminum MacBooks. Apple stated at its event last Tuesday that all Macs would be receiving DisplayPort, so replacing the mini-DVI on current iMacs is almost inevitable.

"This is what we're going to for all video out on all of our products. It's pretty outstanding," said Steve Jobs during the October 14 event. "We can do everything [a full-size DVI] connector can do and more - including driving 30-inch displays - out of something a fraction of its size. Now the new industry standard Mini DisplayPort. We're building it into everything we make," Jobs added.

When it comes to video, there's always room for improvement, and with Apple's fondness of NVIDIA's latest offerings, we trust Apple is interested in using them to boost the iMac’s visuals as well. Currently, the iMac employs an ATI Radeon HD 2400 or 2600 paired with an Intel chipset. An NVIDIA GeForce 8800 GT is available as a build-to-order option. According to the same people hinting at Apple's holiday plans, it is possible that new iMacs are getting solutions similar to those available in the current MacBook and MacBook Pro, namely the 9600M GT. The GeForce 9600M GT delivers faster discrete graphics performance to high-end 3D games and pro applications.

Apple has dated its Q4 conference call with analysts and the press for Tuesday, October 21. It is believed Apple might drop the first hints regarding its new iMac line then.