In a post on the Opera Mobile blog, Opera has announced that it will release the first public beta of Opera Mobile 9.5 for Windows Mobile on July 15th with interested testers simply needing to go to opera.com to download the beta directly and leave feedback for developers.
The post also mentions that there will be as yet unmentioned differences between Opera Mobile 9.5 installed on particular devices such as the HTC Touch Diamond, and the version currently being developed for public release, since Opera Mobile 9.5 is being directly based off of the desktop version which will allow for a standards compliant mobile browser with the capability to browse many more sites than the typical mobile browser.
