This did'nt happen to me before. About 2 weeks since I sync my iPad and iPhone. I have 72 available app updates. When I click update all, A pop up message says updates were out of date and I need to refresh itunes. Now, where is the refresh icon on itunes?
Anyone please tell me?
I close itunes and open again when I could not find this refresh icon. But I can still see the 72 updates available.

Take it to your PC, lap top, Mac, wherever you have iTunes. First make sure you have the latest version of iTunes installed. Allow it to do a sync. If you haven't upgraded you iPad to 4.2.1 allow iTunes to do that for you. After you are done thentry updating again.

75 is a lot of updates for one time, I'm not saying iPad can't handle it but you may want to check your updates a bit more often. I wouldn't do all 75, pick out 20 or so at a time and do it that way.

If you have, in iTunes, clicked on the left column and selected APPS, then previously had clicked "Check for updates" to see if you had any new updates available, then you need to click on "Check for updates" again, this will refresh the list. Sometimes a new update will be added to the app store just after you updated and it wants you to recheck for updates.