Yahoo is preparing to launch a version of its web search software that can be downloaded to mobile phones. 

The company previously released its Go software in deals with phone manufacturers Motorola and Nokia, but the latest version bypasses the need to pre-install the software on handsets. 

However, Yahoo stressed that it will continue to partner with Motorola and Nokia, as well as signing up BlackBerry maker Research In Motion and Samsung, according to reports in the Wall Street Journal. 

Yahoo hopes to capture the mobile market to help it fight Google's domination of the search arena. 

In related news, Yahoo China has announced that it will focus on developing its business search operations. 

Stiff competition from search companies Baidu and Sina are forcing Yahoo to specialise in business searches in the region, according to Jack Ma, chief executive at Yahoo China's parent company Alibaba. 

"If Yahoo is going to win, it has to do so in a new way," Ma told Associated Press. "What's the point of building another Sina.com?"

Yahoo has also announced a new version of its Messenger system that works with Windows Vista. 

The software will use the Windows Presentation Foundation system within Vista to create additional animations and functions.

New features will include larger avatars, easy ways to change the Messenger's colour, emoticons that stretch outside the normal window before shrinking back to a regular size and tabbed messages.

Yahoo expects to release a beta version of Messenger in the second quarter of 2007, with the full release candidate following four to six weeks later.