Android: Skype has been available on Android for a while, but only for voice calling—despite many phones having front-facing cameras. Today, it has been updated to support video chat on over 21 different Android phones.A few weeks ago, Skype added video calling to Android, but it was only available on a few select phones. Today, support was added for 17 more devices, bringing the total up to 21. All supported devices can make and receive video calls from Skype users on any other platform, in addition to the other calling and SMS features Skype provides.
Note that some other devices running Android 2.2 may be compatible, but you'll have to check in the app's settings and check "Enable Video Calling" to get it up and running. If you don't have that option, then your hardware is too old to support Skype. Hit the link for more info, or head to the Android Market to download the newest version.
Skype 2.1 for Android [Skype Big Blog]