Your Odin chip is indeed one of the combo RTC/battery deals, similar to the Dallas chips.

You have two options... you can replace the module, they are still available, but aren't cheap. Alternately, you could hack a new battery onto the existing one.

Those things are usually socketed, BTW.

The CMOS battery is contained inside the ODIN chip. And it's not socketed? That's bad luck. If it isn't socketed, you'll need to desolder it, then you've got 2 options. Both options aren't straight forward. 1) You could physically hack in to it, locate the battery, remove it, replace it with a new one. 2) Solder in a new ODIN chip to the board. The problem with this is a) there aren't any on ebay at the moment. b) if there were, their batteries might also be dead.

Edit: Old Thrashbarg beat me to it! 😀

Well I do have an iron, solder, and wire on-hand. If it's possible all I should need is a pin-out sheet and a watch battery to bypass it with, right?

EDIT: Crap, the only solder I have left is some POS lead-free, and BTW, the chip is NOT socketed to clear that up.

If you manage to remove the chip, it is pretty easy to "hack" it. I've done it in the past for an old soyo board, on which the dallas chip had died. The problem was that every time before running the POST, it loaded the default BIOS values, on which, the hard disk was set to not installed. So it was completely useless without a new chip or something. I think I used this tutorial : http://www.mcamafia.de/mcapage0/dsrework.htm