download palm desktop tool thingy
export to a vcard file, use itunes to import to address, book and sync
or pay $20 and have the store transfer them
Did you have your contacts in a cloud solution like Google Contacts? If so you can just use your Google account on your iPhone.
Since it's been awhile since I've used webOS I don't remember if there is a way to get contacts out of your phone is you synced with a Palm Profile