fastest and easiest way is to just get a card reader and load the songs directly to the card. Another way is to use the palm quick install app that comes with hotsync to transfer songs to the sd card when you hot sync,this will take quite a bit longer.
If you download windows media player (not version 11 only 10) then go to the sync tab. open up your media player on your phone and plug it into the computer. your phone's application should appear on the sync list, if not press f5 to refresh. Then drag your mp3s to the sync list and press sync.