I have an HTC Wildfire S,
Android version: 2.3.3.
I had probems with the new versions of skype (2.2 to 2.7). So I installed the old version 18.104.22.1684 and it worked flawlessly!!!!! Im so happy!
I tested skype over Wi-Fi and I called a skype contact and a home phone number. I will test over 3g and let you know.
I hope it helps
the old versions are on freewareloversdotcom