Ok, I have an Exchange 2003 server. I use Outlook. I realize I COULD and probably eventually will, sync directly to Exchange. However, meanwhile I wanted to sync to Outlook directly. Outlook initially syncs all data to the iPhone with no trouble. However, after the first time, no syncing ever occurs again. Before anything else, here is an excerpt from Apple's support page, which was last updated May 2010. ----- By default, your Outlook data is stored in Personal Folders format (PST) unless you are using an Exchange Server to access your data. If you are using Outlook with an Exchange Server, your data may be stored in an OST file if you have Cached Exchange Mode turned on. An iPhone, iPad, or iPod touch syncing via iTunes will sync with the default PST or OST file. ----- So, they clearly state that it WILL sync with a PST file OR an OST file. Further statements on other pages stipulate that it will only use one or the other. That's ok, I only have ost and related files. Incidentally I did try using the iPhone Configuration Utility to install my Exchange's built-in certificate as a trusted source in my iPhone (which is supposedly a way to do it as an alternative to buying a real certificate). Following every instruction, this consistently failed. Regarding syncing with the OST structure, I spoke with an Apple support agent who then consulted a Senior tech, and they said that it cannot sync with OST - that if I'm using Outlook it either has to be a PST or, if I'm using Exchange, then it has to sync directly to Exchange, not through Outlook. This is clearly in direct contradiction to what their own documentation says. We were able to repeatedly demonstrate using a new, dummy user for Outlook, that the first sync does properly sync information from Outlook to the iPhone, and vice-versa (created one dummy Contacts record on each the iPhone and Outlook, and they both updated both). But, after the one time, it never worked again. I have seen countless articles online that discuss this issue and nobody seems to have a viable solution. Apple says it will work, and it does once, clearly syncing with the OST since that's all there is, but never again. Apple cannot support a feature on their own product! Anyone have any solution for this?