One of our users has more than 80,000 items in his Inbox! This plays havoc with the user's Research In Motion (RIM) BlackBerry device, and the user has trouble using Outlook Web Access (OWA) to access his mailbox. Is there any way to speed up the user's access to his mailbox through the BlackBerry and OWA?

Yes—get rid of some of those items. I suspect an Inbox of that size is a sign of an over-retentive user. No mail client that I'm aware of is engineered to gracefully handle that kind of item count. Given sufficient hardware, most of them will tolerate that type of load but aren't likely to make the process a pleasant experience. If cleaning out the mailbox isn't an option, moving it into a subfolder will help with BlackBerry, OWA, and desktop Outlook performance, even though it won't address the potential problems caused by having such large individual mailboxes.