Google Inc. (NASDAQ: GOOG) just recently launched its Google Calendar for mobile phone usage (as of last week). Sounds pretty boring, right? Well, to most of us, it is. Google, however, sees the future of where people will be getting information from, and it's not the PC. You see, there are quite a few more mobile phones on the planet these days than PCs, and in more markets (except the U.S., yet), customers are using those nice, color mobile screens and higher-speed cellular networks to check e-mail and browse information (not necessarily websites). As such, Google knows that getting its brand in front of customers in that arena is a key move to its future.

Yahoo! Inc. (NASDAQ: YHOO) has not sat still either. "Yahoo! Go" is now being downloaded to cellphones, Treos and BlackBerrys in large amounts, putting the entire Yahoo! portal in front of millions of wireless phone subscribers who still need Yahoo!'s services when away from a laptop or other PC. Similarly, Google Calendar for mobile phones is yet another example of the company making many of its products available for cellphone use.

This is significant because as Google customers begin using its services on those hundreds of millions of phones, Google's advertising finesse could, at some point, reap even more revenue from mobile customers. Google already is playing with mobile advertising and if it can recreate (even partially) the success of its online advertising in the mobile phone space, another mold will be broken. In fact, it will be interesting to see if the same kind of battle will shape up between Google and Yahoo! on the mobile phone screen as has happened on the PC screen.