I think it depends on whether your PDA has built-in WiFi or is just a static unit (like my Tungsten E2) that can only be updated when you sync it with a PC.

My favorite used to be AvantGo but it has been superceded by WAP sites with more current stories that I can access from my phone.

My 2nd fav was Vindigo but it kept crashing every few weeks and thereby lost all my favorites.

The schedule downloads are definitely useful if you are a frequent user of public transit or airlines. But even that info tends to be limited or dated compared with what you can get thru a WiFi connection.

PDAs are presently morphing into iPhone-type devices, and within a decade the old Palms will be museum relics (if they aren't already )