This is the thread. It tells you how to install kexts though it's not too great at explaining how to remove them. Basically when Darwin loads, you type "-s" and then hit enter. Then you're in single user mode. This is the same thing as the terminal. You need to remove the offending kext. I will try to explain it without running the actual commands so bear with me. For each step, type what is in quotes and hit return.
1. "sudo -s" This logs you in as super user, you must type in your password after this
2. "mkdir /problemkexts/" This creates a directory to put our problem kexts in
3. "mv /System/Library/Extensions/name_of_kext.kext /problemkexts/" The mv is for move and this moves the kext to the directory we created
4. "rm -rf /System/Library/Extensions.mkext" I believe this clears the kextcache, but I could be mistaken. It's a necessary step.
After you reboot, you should be good to go. In step 3, make sure you use the name of the kext that you are moving. If you are not sure of the name, you can change directories and list the names of all the kexts with the following commands: "cd /System/Library/Extensions/" and then "ls". There's probably a better writeup somewhere else, but this gives you the basic information.
See also this thread for deleting a kext from single user mode: