I was setting up a Palm Treo 650 to make use of Exchange Active Sync (EAS) for one of my clients.  I'm not that familiar with the Palm O/S as my first exposure to PDA's was an iPAQ 3630. And all of my phones have been Windows Mobile based.  So needless to say there were a few "bumps" along the way getting the 650 setup.  Therefore, I wanted to post a few comments that may help you out if you are in the same situation.

First, the client's phone provider is AT&T (Formerly Cingular) and the phone ships with VersaMail 3.1.  As a result you won't find support for EAS out of the box as that was first introduced in VersaMail 3.5.  So the first thing to do is confirm the version of VersaMail on your Treo.  If you need to upgrade to VersaMail 3.5 you can find an article here, http://www.palminfocenter.com/news/9311/palm-offers-exchange-update-for-the-treo-650/, discussing how to acquire the appropriate software.  It's not that expensive ($12USD in our case) and can be downloaded from the net so you don't have to wait for software to be shipped or travel to a retail store to pick it up.

Once you've purchased the upgrades, download them to the desktop you'll normally sync your Treo with via HotSync.  The default HotSync setup will automatically transfer the upgrade to your Treo and install it.  Once you're running VersaMail 3.5 you will be able to walk through the wizard to configure the phone to access EAS.

The final "bump" I encountered is an embarrassing one.  No doubt somewhere in your career you've encountered the "Is it plugged in?" question during a support session.  Well, this falls along those lines.  The phone was configured as expected, everything looked good and should have been working.  I spent about 30 minutes troubleshooting the issue to no avail.  I was just about to give up when something struck me.  I asked the client if the phone had been setup on AT&T's data plan.  Their response, "What's that?".  So they contacted their rep and added the data plan to the phone.  Once we confirmed the plan was activated we synced again and everything worked like a charm.