A variety of new software for the Apple iPhone will debut this week at the Macworld conference in San Francisco from yesterday until Thursday and the Consumer Electronics Show in Last Vegas from Thursday to Sunday.

Among the early announcements are an upgrade to Quickoffice’s MobileFiles Pro and a remote data service from Soonr.

MobileFiles Pro allows users to edit Microsoft Office applications on the iPhone and iPod Touch. The new version supports Excel files, Wi-Fi connections to Mac and PC desktops, plus access to Apple MobileMe accounts.  It costs $9.99.

Soonr’s eponymous service gives iPhone users access to their desktop files. Instead of working as a standard remote access technology, it moves desktop files onto a Soonr server, thereby doubling as a data backup application.

Users can preview documents as thumbnails and can be manipulated using iPhone conventions such as panning, rotating, scrolling and zooming.

The software is free, although a white-label version will be available to service providers, officials said. Soonr is also noteworthy because it receives funding from Cisco Systems.

In the United States, whether programs like Quickoffice and Soonr files will act as solidly on first-generation iPhones is another story.  To clear spectrum for 3G networks, AT&T may be moving parts of its 2G network from 850 MHz onto the weaker signals of 1900 MHz systems, according to various industry blogs this week.

Meanwhile, Apple CEO and co-founder Steve Jobs today wrote an open letter to the Apple community, atrributing his recent weight loss to a “hormone imbalance”.  Jobs said he is undergoing treatment that is “relatively simple and straightforward” although the charismatic leader did not say if his illness was related to a previous bout with pancreatic cancer.

Jobs, Steve Wozniak and Ron Wayne formed the computer company in 1976. Wayne sold back his share after two weeks.   Jobs was outsted as CEO in 1985 and reclaimed the role in 1997.