Text Me! - Free SMS & MMS like Messenger for iOS device

This is something like SMS in instant messaging.

Features : 
• Send & receive free rich text messages around the world from iPhone/iPod/iPad to iPhone/iPod/iPad
• Push Notifications for new messages 
• Super simple registration process, no email or password required.
• Send and Receive Pictures & Videos
• Group Chat 
• Scheduled messages 
• Web client for your friends 
• Available in 9 languages : Arabic, English, French, Hebrew, Italian, Korean, Portuguese, Slovak, Spanish
• 4 delightful themes and customizable backgrounds
• 367 Smileys

But it's not real SMS... it allows you to send videos though :)

Download link: http://itunes.apple.com/us/app/text-me-free-sms-mms-like/id338088432?mt=8#