Opera has just released their first (preview) release of their Browser for the Maemo platform. This should work on the N900, along with the older N800 and N810 devices. They’ve also said that this version is not an officially supported release and does have a few bugs. Here’s a snip from their labs post about this release:
This Maemo version of Opera Mobile 10 was created as a hobby project by a small team of developers in their spare time. In total, about 6 man-weeks were spent on creating the release. It’s worth pointing out that this is not an officially-supported release. As such, it has not undergone our usual quality assurance processes, and at times may not feel as polished or complete as an official release. This also means that there may never be a “final” release of Opera Mobile 10 for Maemo devices, since it’s just that much more fun to add shiny new features rather than fixing boring old bugs.
There are some known issues with this release with the notable fact that the Flash plugin is not yet supported, and power management support is missing. So don’t keep the browser on when you’re not using it, or you’ll end up with a dead phone.