Although the iPhone is definitely ascendant, I find myself getting frequent requests from friends for information on how a BlackBerry works and how they can share calendars etc. Here's a basic tutorial.
If you buy a BlackBerry as a consumer user, it will be configured with the Blackberry Internet Service. This service allows you to direct a copy of all your e-mails through the Research in Motion servers (the company behind BlackBerry) so that they can be "pushed" to your device. Calendars and contacts are synced only when you connect your computer with a cable (or bluetooth) and use the BlackBerry desktop software.
But if you want wireless sync, there are several options.
The easiest is to use Google Calendar and wirelessly sync that calendar with your BlackBerry calendar. You do this by downloaded a sync software from Google to your Blackberry (LINK). After you set it up (really easy) it will sync your Google and Blackberry calendars. I have found that it works seamlessly but it is Beta so your mileage will vary. Also, I suspect but am not sure that it's this sync function that periodically slows my BlackBerry to a crawl, especially right after I turn it on. Not too much of a bother but annoying nevertheless. But the main trouble with this solution is no sync of contacts.
A partial solution to syncing contacts--at least if you use GMail--is to download the GMail for BlackBerry application. There's a new BlackBerry ap from Google that lets you not only download that ap but also others such as Google maps (LINK). This application allows you to use GMail directly from the Blackberry and also access contacts stored in GMail. Challenge is that it's quite slow. I use it mostly to lookup e-mails from my Blackberry that are stored in GMail. (Note that if you use GMail for Applications, rather than the standard GMail, there's a separate application for that that looks and works identically, except that the icon on the BlackBerry is blue rather than red.) An additional component of this solution, if you want to sync your calendar back down to Outlook, is to use the Google Calendar to Outlook sync (LINK). But if you go this route, make darn sure that when you sync your BlackBerry using the BlackBerry Desktop software, that you do not re-sync the calendar or you'll be getting duplicate entires.
The full solution is BlackBerry Enterprise software (LINK). If you install this, you'll have full wireless sync of calendars, contacts and task items. Whether you go for an installation of this software on your own Microsoft Exchange server or make use of a hosted version of the production (LINK) like the MailStreet service (LINK), this requires a person with a decent understanding of Exchange servers. Setup will require them on site with your Blackberry devices in hand. The base level version of this solution is about $500.
A solution that BlackBerry has been talking about but isn't out yet in the United States (though it is out in Spain) is BlackBerry Unite! (LINK). Unlike an Enterprise software installation, it's free and setup is on a desktop machine rather than a server. Designed for up to five users in an office or home environment, it seems to provide the core wireless sync benefits of the Enterprise server. But I'm not certain if it really will provide full wireless calendar and contacts syncing. And I don't know when it will be more widely available and which wireless carriers will allow the product.