A beta of Opera Mobile 10 for S60 was released today. Now S60 also gets a taste of Carakan and Vega, and they've also added support for Geolocation. Note that JIT has not been enabled in the S60 version yet.
There's also good news for Maemo users. The unofficial Opera Mobile for Maemo project has released an update based on the latest 10.1 code, and those lucky N800 and N900 users out there even get Carakan with JIT!
However, the Maemo build is still unofficial, and it's so experimental you should only try it out if you are absolutely sure that you are willing to risk things like loss of data. Once Opera Mobile 10.1 for Maemo has been tested a bit, I believe it will be pushed as an update for all current users of Opera Mobile 10.
If you are into beta (or alpha) testing of mobile browsers, be sure to check these out.