Ok. Here's what you do:
I am going to assume the phone boots to what is known as hboot.
First, you read up on fastboot commands; always good knowledge. Link to start you here:
http://wiki.cyanogenmod.com/wiki/Fastboot
You will need workstation, android sdk installed, usb cable and phone (of course), and aforementioned knowledge.
Alternatively, but not quite as thorough, download a good recovery like the one found here:
http://forum.xda-developers.com/showthread.php?t=1213229
Ok.. so you either want to:
fastboot erase ...
system, userdata, cache and boot
To get recovery to the root of your sd use adb:
adb push (whereitis) (whereyouwantit... ie /sdcard/PG76IMG.zip)
or use cwm to mount and format pretty much same (if you choose that route).
Now, you are clean... don't flash w/o reading that the rom is for your device.. This one still only one I know of, but development is acoming.
Mainly although it's not something you might choose to wipe between every rom install, in this case, and for anyone that's accidently flashed gsm, you need to wipe your boot partition now... It's what I like to call wobbled.
Ok so we're clean... Download the rom in OP and rename it update.zip; use the aforementioned adb push to put it on the root of your sd card. Also, may want to move that recovery to a subfolder (so you can get by hboot's startup). Now you can flash the update.zip in recovery as normal. Everything should be golden. Hope that helps.
Regards,
Rob