The company has also released something called the App Directory, which is an online database of iPhone and iPad apps that will work in conjunction with Dropbox and its file sharing capability. You can browse, review, and rate Dropbox compatible apps (and actually, Android, Blackberry, and Windows Mobile apps are included as well, if you happen to have one of those phones), and even follow links straight from the listings to download and use whatever apps you need. If you save a lot of things on your Dropbox account, you might want to take a look through there. There's standard stuff like GoodReader and Documents to Go, but odds are that, even if you've found another use for sharing on Dropbox, there's probably an app to help you do it.
Note: Please don't put Dropbox referral links in the comments. They will be deleted, and repeat offenders will be banned.