In terms of providing access to the key information that lurks within a company's files, however, the secret sauce lies in both the database and synchronization software that usually exists on the server side with some thin client pieces installed on the mobile devices to coordinate handshaking, security and final presentation of the information. There are lots of companies that provide really good third-party software that is designed to open small windows into a central data base, channel information to a variety of different mobile devices, and then provide synchronization techniques that allows remote users to update information on the server side.
Some of these solutions work through a dedicated system attached to an enterprise server and protected by a firewall, and can be used to synchronize data on remote devices. Others work through the Internet and third-part services and applications that provide synchronization and update procedures -- although many companies view this as a less secure tactics than firewall-protected systems.
Most multimedia-enabled phones these days, and certainly so-called "smart phones" offer some kind of standard synchronization software that lets you channel information -- like contact updates, e-mail and even sales order info -- between your mobile phones and host PCs. The wireless carriers are also working with a number of synchronization and mobile applications development companies to offer enterprise-class services as part of their standard business billing platform. So, the first step might be to check with your service provider to see what business services are on their wireless menu.