Man, there really should be an R-09 FAQ posted or something... I know it's a lot of pages to sift through, but I know some of us have been reading every page thus far. Having said that... if I'm wrong on any of the following info, I welcome correction(s).
bluntfortrauma: YES, you can use a 4GB card with the R-09. People are reporting successfully reading/writing to a Transcend 4GB card. The R-09 will NOT format the card; you have to do perform the format under Windows or using a card reader apparently. That part is based on my own understanding from reading other's posts. I do not own a 4GB SD card (yet).
YES, the R-09 has a HOLD switch.