I caught this over on Engadget but they were not even correct on how to get past 500MB. This offer goes for both Computer and Phone clients. However to get the entire 5GB increase requires uploading 4.5 GB worth of files. I recommend using the computer clients because of this.

The phone client once installed will automatically find files to upload to your drop box and begin uploading. Shortly you will have your 500MB for the first file upload. For every 500MB of files uploaded you gain 500MB of space. The Windows client relies on the autoplay feature and in Windows 7 camera's have their own dialog. From this dialog you just need to change the "Import Pictures and Videos" program to drop box and send it on its way. Remember at the end of this import the files are probably still being uploaded to dropbox and until this is complete you wont get all your space.

Computer client downloads - (2/3) - Experimental Forum Build - 1.3.13 ? Dropbox Forums
Android Client - (2/2) - Experimental Android Forum Build - 2.0.9 ? Dropbox Forums

Those who completed the minimal steps before have at least 2.25GB unless they invited a friend. My friends never took my invites so I should be sitting on 7.25 GB when this is all done.

That's nice and would be very handy. I was reading a little of the forums and people did not like that the files are renamed. I wouldn't either and some say they would not use Dropbox for that reason. Do you know why they rename the files?

Well I dont use that feature of it so it would never be a problem. Did what I needed todo for the space. But quick guess would be naming them by upload date and time would mean never having to prompt the user about renaming files when the same name pops up. Most cameras only do 10,000 files before recycling names again.

Makes sense. I should try it sometime just to see how it works because some times I do find myself emailing photos to get from one device to another.