The tried and true approach to sorting out the linux compatibility of anything is to boot the machine in question with a live distro. Should everything work, then you are home and hosed ... nothing left to do.
Some things don't work, then you can use the live distro to interrogate your hardware to find out what it thinks it is. The "lspci" command is good for this, as it will report what the hardware is instead of whatever misleading trade-name the vendor uses.
There is a sticky in this very forum which explains the sort of information that is useful and how to get it out of linux. It is called something like "how to post to this forum" or something of that nature.
Enough of the general: your mobo will be something like the following...
http://www.cpu3d.com/index.php?optio...id=418&limit=1
If so then congratulations on an excellent choice.
This uses an intel chipset base - so should be well supported out of the box - you probably won't need any additional drivers. Install and away you go.
It is an enthusiasts board - if you are using the dual ATI cards, you will be looking at the proprietary driver... this is well documented.
It uses SATA - you may need to set sata to legacy ide for the installation for some distributions.
Intel HD Audio - some people have been having trouble with this. There is a driver but it works best in very recent kernels. Be prepared to upgrade the kernel after installation. (You should do a general upgrade anyway.)
May I suggest: Ubuntu Feisty-Fawn for this board.
Basically, you want a very recent release (Fedora Core 7 should be good too) and you don't want to be messing about with custom settings and installing drivers while you are getting used to the way linux does things.
Once you feel comfy though, I would suggest you consider a more customizable distro like slackware or gentoo.