Some users still use old WindowsMobile (PocketPC) phones (version 6.0, 6.1 or 6.5). Some of them might need to use skype. At this moment, I dont know if it is still available to install skype on PocketPC, however you can try to install that.
You can try to download it from here or here. If non of them works, try to search in google, but remember to download software from trusted site (btw, I dont think you should take care of security of your WinMobile too much. If so, then download whatever you want). The "must-have" recommendation: update your phone, get Android and forget Windows Mobile forever, if you need to simplify your life.
p.s. View other useful apps/software for Windows Mobiles (6.0 - 6.5).
