There really isn't a "cab" for the iGO8, that cab file would actually be humongus!! If you check the website
http://www.navngo.com/pages/global/e..._8_description it comes with its own mini SD cards. However with the right size micro SD and the know-how
http://forum.ppcgeeks.com/showthread.php?t=88692 I am quite sure that you could possibly figure it out!! Best of luck!!