EMS...

Enhanced Message Service (EMS) is an extension to the SMS standard that allows the transmission of icons, sounds, melodies and other rich content.

Ultimately hundreds of thousands of images (like icons), melodies, sound marks and animations will be available to add pizzazz to your messages. Download images from online libraries, or create your own right on your phone using the built-in picture editor. Or do both - download an image you like and manipulate it to suit your purpose. You can also download simple animations or alternate multiple images yourself to create a custom animation.

Melodies too can be either acquired ready-to-go or created for a more personal touch. And unlike SMS, EMS allows you to download and exchange the wide variety of ring tones avail-able online. In fact, you can exchange all your favourite pictures, animations, melodies and ring tones with your friends.
 

MMS...

Multimedia Messaging System (MMS) is the logical evolution of the Short Message Service SMS, a text-only messaging system for mobile networks. MMS-enabled mobile phones enable subscribers to compose and send messages with one or more multimedia parts.

Mobile phones with built-in or attached cameras, or with built-in MP3 players are very likely to also have an MMS messaging client -- a software program that interacts with the mobile subscriber to compose, address, send, receive, and view MMS messages.