Yeah go for the 6230 if the 6230i is out of your budget. I have the 6230 and it is a great phone. Loaded with features in a small and compact package. It uses the normal MMC as grudge said and not RS-MMC. You can safely put in a 512MB card in the phone without any issues. All that will happen is that the phone will take a long time to read the data stored on the card. So if you are playing music, it will take a long time to read all the tracks on the card. I would recommend a 256MB card instead-I think it provides a good balance between storage size and usability. It will also be cheaper of course
Oh and yes, please post future cell phone queries in the Sticky.