I am curious as well. I just bought my fiance a 8100 want to get her more memory and I also cant get any clear answer as to if its compatible with sdhc cards. I do know that if you go to the t-mobile website and use there automated accessories option, select the 8100 and then select memory, the only choice that appears is a 8gb sdhc card? So I am to assume that current OS supports sdhc cards. I bought her a 4gb sdhc off ebay today for 8.00 so well see.