The bane of mobility is battery life. I think pretty much everyone is in agreement on this point.
In about a year, we may get some relief. M2E Power will be introducing a charger based on motion to create energy to charge mobile devices. I imagine it'll be frictional energy will be converted into electricity to charge the mobile devices. According to Symbian Freak, they are reporting six hours of motion can add 30-60 minutes of additional talk time to a mobile phone.
It depends on what kind of mobile warrior you are but it is difficult to imagine anyone move around for six hours each day. However, until we know what kind of motion and how strenuous it has to be, we can only imagine the applications for just such a charger. There could be a wide range of military applications. For recreational purposes, people who go on hikes or camping trips.
The article seems very optimistic about the prospect, I'm still a bit more reserved about how well it works and how our mobile behaviors may be changed by this. Are we more like to take walks to the water cooler to make sure our phone has a extra minute of talk time?
To be sure, when I go for a run carry the charger and my iPod with me, it may be something that will interest me greatly. Personally, I'm very interested in renewable power and this sounds like one of those.
So, just to recap a bit on some alternative charging formats, there is solar, wind, and now motion. Now, I'm just waiting for the point where solar backpacks are efficient enough to charge super-efficient laptops. Then I'll be happy.
Again, the impact of such a device may be extensive but we won't know until it's actually in use.