syncing calendar and address book

I would like to know if anybody knows the best way to sync calendar and address book between two computers (1mac & 1 xp window's machine) I have a palm that I mainly use on my xp machine (desktop), but would like to keep everything synced with my new macbook. Any help would be appreciated.

In this case, the Palm would be the go between for both machines. Sync it to both and then sort out all of the conflicts on the Palm. Then sync it again with each, but have the Palm over write both machines. Once you do that, the palm will be the main device used to keep both machines sync'd together.