SAN FRANCISCO - APPLE on Thursday laid out the launch of the hotly-anticipated next-generation iPhone 3GS smart phones amid renewed speculation regarding the return of Steve Jobs to the firm's helm.

US telecom giant AT&T said that 3GS iPhones will be available on Friday morning at 2,200 of its retail stores and at all Apple stores in the United States.

AT&T said that 3G-S iPhones pre-ordered from it online are being shipped. 'The time is finally here,' said Ralph de la Vega, president of AT&T Mobility & Consumer Markets. 'We're more than ready to open our doors tomorrow and begin selling the fastest, most powerful iPhone yet. We understand that customers are eager to get their hands on this great new device.'

A 16GB iPhone 3GS costs US$199 (S$290) while the 32GB model is priced at US$299, providing buyers sign up for service contracts with exclusive US carrier AT&T.

The prices of iPhone 3GS models jump US$200 if buyers don't match them with qualifying AT&T service plans. Pricing for service plans begins at US$70 per month, according to AT&T.

Apple followers are watching to see if Mr Jobs coincides his promised return from medical leave with the iPhone 3GS market debut.

'This is an opportunity for him to appear, but if he is looking really frail they are not going to put him in front of an audience,' said analyst Rob Enderle of Enderle Group in Silicon Valley. 'He's got to the end of the month.'

Mr Jobs, 54, who has been on a medical leave of absence since January.

Apple has been secretive about Mr Jobs's health since he underwent an operation in 2004 for pancreatic cancer but has been adamant that he is returning to the company's helm at the end of this month.

Apple vice-president of marketing Phil Schiller took the place of Mr Jobs this month at a developers conference presentation and unveiled the iPhone 3GS, which is the first model to have video camera capabilities. -- AFP