Gmail may not be strictly for contact management, but its popularity and position mean that the majority of your contacts are probably already there. Combine a rich contact management tool with one of the Web's strongest mail services, and you have a safe place to store information for everyone you know. Best of all, since it's not on your phone or SIM card, you can access it from any mobile device.

ReQall is a free to-do and reminder service at its core, but one of its best features is its ability to assign to other people to-dos that you enter into it. Talk about an incentive to add everyone you know to your account. Once you have all of your contacts listed, looking up an address or phone number is simple. ReQall is available via mobile web, but has special clients for the Blackberry and iPhone.

Services that archive your contacts are great, but if you exchange business cards over drinks, how do you get that information into your phone? ScanR can help. The app is available for Symbian, Blackberry, and Android devices, and uses the camera in your phone as a scanner, reading the text from business cards and cocktail napkins alike. ScanR will even save contact information from a business card as a contact on your mobile phone, or e-mail whiteboard notes to your coworkers.