How do I send multiple photos to one email contact on iPad?

When viewing your photos in thumbnail view in the Photos app, tap the icon top right of the box with the arrow coming out of it and you should then be able to select up to 5 photos for attaching to an email via the Email button top left on iOS 4 (Share > Email on iOS 5).

Using the Photos App you can email up to 5 photos to an email recipient(s).

In an album select the share icon, select the photos you want and then select email.