Today I've just installed Skype on a Nokia 500 mobile phone.
Before doing that, I upgraded the phone software to Symbian Anna version 011.033.
At my PC, I downloaded the software from this official link: http://blogs.skype.com/garage/2011/04/skype_20_for
I transferred the file to the phone, and then I installed the application from there.
The 1st time I started Skype from my Nokia500, it seemed to get frozen. But after a while, the application started without any problem at all.
FYI, I've done some successfully test calls (without an exhaustive use of the application).
EDITED: I'm not sure if this skype version will have some problems with our Nokia 500. So take care, and before installing the application let's do backup of the phone (Nokia Ovi Suite).