*UPDATE* - It's been pointed out at this time the Storm 2 has this feature built right in so users will not even have to download the app to use it, that version is at 126.96.36.199 but, it's not know at this time if that will be standard across future devices as of yet.
We've been hearing for a while now that RIM was working on a plugin for Gmail users that was going to bring a bunch of additional features when it came to handling Gmail on your BlackBerry. Finally, it is now available for all users to download--if you can get the link working right, RIM seems to be having issues with the links issued via BIS accounts, but have an alternate page as well. The new plug includes some great new features for Gmail users such as:
Synchronization only happens from your BlackBerry to your Google Mail account, meaning some changes made through your Google Mail account won’t sync to your BlackBerry(One way synch). In order to get the download link if you already have a gmail account set up on your BlackBerry you will need to delete and re-add your account and a PIN message will be sent to you with the link. The enhanced plugin is available for all device 4.5 OS+ and the official BlackBerry forums has a great getting started guide available. Visit blackberry.com/gmail from your BlackBerry's web browser to download.