Just over a month ago, Samsung sent out free Galaxy S II's to a few of the developers behind CyangonMod with instructions to get CM working on the uberphone as soon as possible. The first real sign of progress came a few days ago when they released a video showing CM7 running on an SGSII along with a message that nightlies would be following soon. Well, we're happy to report the first official build is now available to download and install.
First off, you have to be rooted. If you're not already rooted, check out this XDA thread and follow the instructions. To flash the ROM, you can either use ROM Manager, or manually flash the ROM. Instructions for either can be found in the Official SGSII CM7 thread on XDA, though experienced modders should know that flashing this is no different than flashing other ROMs. In a nutshell, the manual method: boot into recovery, wipe all the things, and flash the ROM. As with other CM builds, you will need to flash Google Apps independently; this can be done simply through ROM Manager, or manually by downloading and flashing the APK.
Get flashing, SGSII owners, and let us know how things feel in this build. If you need support, your questions are best directed to the relevant links above.