[AT&T Samsung Galaxy S II SGH-I777] BobbyBlue:
Update is being pushed out slowly, but I figured out a way to forcibly do it in kies.

It simple. Do not plug in your phone while you are doing this.

First, make sure you update to the new version of kies. Then go to the menu bar> tools, then firmware upgrade and initialization.

Click until you get to the screen that asks you to input your S/N and Model name of your phone. Enter in these details. It's behind the battery.

Once you do this, a screen will pop up asking if you are sure you want to upgrade to CSC:LE5. AKA ice cream sandwich.

At this point, plug in your phone and it'll go through.

Your welcome.

EDIT: as of today, Monday June 25th 2012, at 11:00 AM, the update is officially available through KIES. If you don't see it now, a popup telling you to upgrade will appear by tomorrow.

EDIT 2: DO NOT UPDATE TO ICS. IT SUCKS. AND IT IS NOT NEARLY AS SMOOTH AS GINGERBREAD. If you hate android lag, the update will almost certianly piss you off. If you have questions about how its different, just ask. I already downgraded to gingerbread again. ICS = Not missed.

EDIT 3: (copy pasta from a post I made)

No. I assumed that the update through kies updated the bootloaders, so I found a stock 2.3.4 one click odin executable W/ Bootloaders in the development section and flashed that. Make sure you factory reset and clear cache in 3e recovery before you do so. New bootloaders can't take advantage of the Jig. I also didn't want to find out what flashing gingerbread on ICS bootloaders would do my phone.

I find 2.3.6 has battery issues, and I find 2.3.4 to be THE most stable release.

http://xdaforums.com/showpost.php?p=20229527&postcount=46

The file you want from this page is the I777UCKH7-CL503881 Stock Binaries, and you want the odin3 one click download. It's one of the ones with the warning text in red.

To restore your phone to stock 2.3.4 once on ICS do the following:

1) Boot into 3e recovery (power + volume down + volume up)

-Wipe Cache

-Factory Restore

2) Pull battery

-boot into download mode (volume down + volume up, then connect phone to computer while buttons are simultaneously pressed)

3) Open the one click executable. Make sure it recognizes the phone

-It will say [COM8] or something. Just make sure its green.

4) Flash it. It will work. after you boot up into gingerbread, If the system freezes after the At&t logo just go back into 3e recovery and wipe cache + factory reset again. It will work. Trust me.

Note: ODIN is a very tricky piece of software. When you click flash, it will probably not work and say "failed" or something along those lines. Try it again. It will work. It took me almost 20 tries to get the flash to go through. Also try flashing it as soon as you plug in your phone (not even 2 seconds after it is recognized). That seems to work. Don't be worried if it never seems to go through.

Note: YOU ARE FLASHING BOOTLOADERS. PLEASE PLEASE PLEASE BE CAREFUL. If ODIN DOES NOT WORK OR YOUR COMPUTER SHUTS OFF HALFWAY THOUGH, OR ODIN QUITS, NEVER PULL THE BATTERY FROM YOUR PHONE. As long as you see a downloading sign on your phone, your phone is ALWAYS recoverable. Just open up the odin executable again, make sure your phone is recognized, and restart the process. If odin freezes halfway through the process, always restart odin, NEVER touch your phone. Your phone can always be written to while in the download state. This is how 99% of all bricking happens, because people always feel the need to turn off their phone in the middle of the process.