In theory (meaning, I don't use Yahoo so have not verified) you can use SyncML to get at your contacts and calendar. You will need a SyncML client for your Pearl ($30), and then try these settings: http://go.yahoo.com/next/product_syncml
Try reading this thread (it's not really linux specific, don't get scared off) to help you understand how to make it all work: How to: Sync BB if you use Linux / Unix
Just replace all the "Mobical.net" stuff with the Yahoo! information in the first link, then see what happens. The good thing is that you can download a trial of SyncJe for your Pearl for free to see if it works *before* shelling out $30.