It is making Opera Mobile 9.5 available as a technology preview, and it supports Google's Gears. Opera's Andreas Bovens writes, "The use cases for Gears differ somewhat between mobile and desktop devices. On mobile, Gears is perfect for creating a better user experience by allowing applications to cache data more efficiently, so you can cut down on bandwidth, and carry out processes discreetly in the background."
Developers can use Gears to permit offline access to their Web sites, for starters. This can be accomplished with a number of the APIs in Gears, and can let users interact with the mobile Web (with limitations) when offline.
This all sounds very promising, but it will be up to developers to make it happen. The "technology preview" being offered by Opera is by no means a final product. Some of its success will hinge on the desire of developers to create offline access to Web sites and services.