Yes. While there is no standard for what the About should contain, it is in fact very useful. I especially think this holds true for popular applications.
The "About" in terms of an application will normally contain a summary of info about the Application itself, such as:
- Summary of what the app does, why it was developed.
- Version info, which comes in handing when the user needs support.
- Developer and contact info.
- Support info.
- Legal info.
This is just an example of what can be added to it. And some will find if very helpful for you to store that info with each version of your app.
And since almost any website you visited contains an "About", because most user may want to have some basic information on the person, and or service the website is for; The "About" page is just for that. And rightly named so.
In my opinion, it is VERY important. Also I find it annoying that on the iPad; I have to leave the App and go into the App Store, or log-in into my apple account, just to find the version info. Although some iPad App developers were smart enough to put it in various places, like in a pop-up screen when you click an info icon on the main screen of the app. However, I would like to see a more standard place like with desktop Apps and websites.
Even Google has one on their home page on the lower right corner, check it out.