To install supported files from a Mac, please follow these instructions:
Via hotsync:
Open Palm Desktop, go to the Hotsync menu and select "Install files".
Open a Finder window and browse to the folder where your MP3 files are stored.
Select the files you want to copy over, and drag them over to the Hotsync install window.
Then do a hotsync to transfer the files.
Note that hotsync is very slow transferring files, so this could take some time.
Via card reader:
Insert your card into the reader and plug the reader into your computer.
Open a Finder window and browse to the folder where the files are stored.
Select the files you wish to copy and drag them to the card.
Note that the default folder for audio files with Pocket Tunes is the /audio/ folder, so you may want to create that folder on the card before installing the files. Otherwise you'll have to browse the card for files each time you select different files to play.
Another option is to use Missing Sync from Markspace which allows for syncing of playlsits from iTunes.