Gretsch, the interior leather slit pocket that you are referring to is still small. It fits a normal cell phone perfectly, but not a PDA. You could always put your PDA in the somewhat larger interior zip pocket, though- just leave it unzipped. Or keep it in one of the outside pockets of the bag.
There are some online stores selling Tano bags at discount prices that charge restocking fees on refunds, consider all sales to be final, ship shopworn goods from their bricks and mortar store's shelves, etc. So as with any online purchases, be sure that you fully understand the stores refund/exchange/service policy BEFORE you buy!