What is the latest working version of Skype for G4 running 10.5.8 Leopard?

Hello! I have tried to dowload the latest version of skype (that is 5.3) for MacOS X from Skype. Unfortunately it doesn't run and says that it is designed for another architecture (that is for Intel platform based Mac's). The What is the latest running version of Skype for non-Intel platform based Mac's? I have tried searching the discussions and I couldn't find the answer, just the users facing the same problem in the past. Please help - Skype is my main instant messenger. Thanks!