Great news for all N770 users! Someone discovered that is possible to make Skype run on N770 with Os2007 HE.
All you have to do is follow these steps:
1. Install skype-ui through Application Manager
2. Download this package in your PC and extract the file named skyhost
3. Find a way to copy the file skyhost to your maemo device in /usr/bin
4. execute this from root on your device: chown user:users /usr/bin/skyhost
That's all! You can find more information on the original post.