You may want to make a reduced size view for say an input box of some sort or a view that will be used at the same size for both iPhone and iPad devices.
Setting the View Size
Select the view. In the attributes tab ensure that ‘Staus Bar’, ‘Top Bar’ and ‘Bottom Bar’ are all set to unspecified/none (you can’t resize a view if any of these are used).
In the Size tab set the view size you require and how to position it on the screen. The device screen sizes are:
iPhone 3 320x480px
iPhone 4 640x960px (although interface builder work to 50% of this to match the iPhone 3)