Several users have reported an issue in which iTunes 10 crashes when click on the Apps tab of the sync pane.
Fix: Make sure there are apps on the first screen. In most cases, this issue can be solved by simply ensuring that the first screen of apps is not blank, i.e. it must contain at least one app. If you’d like to keep the first screen blank, you can workaround this issue by simply dragging an app to the first screen then syncing, then removing the app again.