Is there an app that will tell you the total Mb being used by each installed app? I know you can get this info from iTunes once iPad is connected but I would also like to view this info without connecting to pc.

I'm not aware of any app that does that on the device. Apple don't allow apps to interact with the whole file system because of their sandbox approach. I could be wrong, but I don't think one exists.
You can see the storage used overall and the number of apps you have in Settings > General > About

The app store app on the ipad lists the size of each app. I always check this before I download, and sometimes after to see which are the big space hogs.

There's no app for this, but you can see the size of each of your installed apps in iTunes when you have your iPad connected to your PC. There's a "list by size" option which is quite useful.

Thanks everyone for your replies. Guess I'm stuck with looking it on iTunes. Cheers.

It might be interesting information, but what would you do with it?

Make an informed decision as to whether I wish to delete a large but useless app!

If it's useless, why delete it now, regardless of size? You can check app sizes on iTunes, fwiw.

Yes I know you can get this info from iTunes . If you read my original post at the top of this thread that's exactly what I said!