Wi-Fi hotspot aggregator iPass has extended its service to support Windows Mobile 6, the company said this week. At the same time, iPass announced its network has passed the 100,000 mark.

iPass' Mobile Office service supports Windows Vista, Windows XP, Windows 2000, Mac OS X 10.5 (Leopard), Windows Mobile and the Symbian OS. iPassConnect mobility service for individuals supports Windows Vista, Windows XP, Windows 2000 and Windows Mobile. The company is planning iPhone, iPod iTouch and BlackBerry support for later this year.

In further expanding its network and its support for handheld operating systems, iPass renewed the debate around whether large, aggregated Wi-Fi networks are a viable alternative to other wireless connection techniques such as 3G.

"iPass' mission is to simplify the growing complexity of enterprise mobility, and expanding support to these platforms is a key element of our strategy," said Joel Wachtler, iPass' vice president of marketing and strategy, in a statement.

iPass argued that its Wi-Fi network compares favourably to 3G coverage, citing research showing that even in US city centres, 3G is available only 60 percent to 70 percent of the time, due to signals being blocked by hills, trees and other obstacles.

3G is also often unavailable outside of city centres, the company said.

iPass is not the only organisation criticising 3G coverage. Industry analysts In-Stat warned recently that 3G coverage is particularly limited by the fact that it degrades or disappears indoors, a factor the company said is holding 3G back.

In-Stat is urging operators to use microcells, picocells and femtocells to address the problem.

iPass argued that Wi-Fi networks are the best way to avoid the high data roaming charges from cellular operators.

The European Commission warned in February that data roaming charges in the EU are too high, and said the industry faces regulation on the matter.

iPass is not the only Wi-Fi aggregator taking advantage of the limitations of 3G to push its services.

Earlier this month The Cloud launched a Wi-Fi access technology called mycloud to make it easier for customers to find and use hotspots, arguing the technology brings Wi-Fi access a step closer to remedying 3G's shortcomings.

"Wi-Fi is faster than 3G," said Owen Geddes, The Cloud's business development director. "Also, 80 percent of data transactions are inside buildings, and 3G's in-building penetration is not great."