Please note that when it comes to emoticons, Android is different from iPhones in that it has a built-in emoticons system. This is what most users do when they want to send emoticons. There are also some 3rd-party emoticon apps for Android, but these cannot be viewed/sent inside Viber text messages since the apps themselves don't support Viber's messaging textbox.
The only possible solution for emoticons inside Viber is for us to develop a built-in emoticon feature inside Viber, and that is something we are considering doing, but we still don't know when that will happen. Meanwhile, the more users request it, the greater the chances that it becomes reality. Here is the link to our feature request form in our HelpDesk: Have an idea for a new feature? | Viber Support
Viber for ICS is coming soon - our dev team is working around the clock to complete it ASAP. Once I have news, I'll let you know.