1. Reboot into recovery.
2. Using the recovery menus, mount /system
3. Through adb, push the su binary from http://magicandroidapps.com/su.zip to /system/bin/ [NOT the zip file, the file inside of the zip file. It will just be named "su" without a file extension.]
4. chmod su to 6755
5. unmount /systemCode:chmod 6755 /system/bin/su
Oh, and this will only work on other roms without root if you have a custom recovery that allows root access to the device through adb. [Such as SirPsychoS' recovery menu]