You can download the consumer version of the app at https://m.google.com/mail. Google Apps users need to download the Apps version at
Users at PinStack Forums report that a significant change with version 2.0.5 of the app is the ability for a user to store the credentials for multiple Gmail accounts and then switch between the in-boxes for those accounts without having to keep entering a password.
Another cool addition with this version is that you can now copy-paste text within the app.
An important consideration depending on your BlackBerry data plan, Google notes that the device “runs in the background, periodically checking for email.” If you’re not on an unlimited data plan you may want to shut this process off by going to the app’s menu and choose “Exit Gmail.”