Some days back iOS 4.2 GM was released and its already out, the final version is to be released in some days and we will be informing you about the release date soon as it gets its update..These will be for all old models of iphone and ipod touch as well including the iphone 3Gs .
There seems to be the Hardware, which is causing the main problem due to which old iPhone models wont support the features like the multitasking ,FaceTime and others as well..
These hardware were upgraded in all the latest models of iphone,ipod and ipad the hardware ware upgraded in iPhone 3GS which supports the multitasking but if we got the news that tht iOS 4.2 wont support in the older models of iphone like the iphone 3G but there is a video which is uploaded by Rene on TiPb shows that iPhone 3G is also compatible to run iOS 4.2 without any lag and sluggishness with full speed like in phone 3GS and iphone 4.
Here is a video that he has posted which iphone 3G running on iOS 4.2 and performing all tasks like typing, zooming, scrolling, opening apps and other apps etc.
