I have some good and bad news for you.
Good News: You can use Skype with your X3-02 model phone. I have been trying everything to use Skype with my mobile and found a way. All you need to do is to download Skype Lite from that link http://handheld.softpedia.com/progDownload/Skype-N
I chose Nokia N95 [JAR]. Others might work, too.
Bad News: It's not for X3-02. So, it is not easy to use. When you want to choose something on the screen, you normally touch on it. It will not work with this Skype and X3-02 combination. You will need to drag and leave your finger on what you want to choose. You will see 2 small grey squares in the middle of bottom line on the screen. That is the OK/Selection/Confirmation button
IMPORTANT: Unfortunately, it charges (from your Skype credit) when a Skype user calls you. However, it is free to call a Skype user. If you do not have any money in your Skype account, it means that other users can not call you. If you have some Skype credits and do not want to be called by others, you can choose it from settings.
Skype chat works properly. So, I think, the best thing to do is your friends can write you when they want to talk to you and after that you can call them.
I hope that will be useful for you.
Interesting did not know about that app, but it cots money to call Skype friends - sounds really strange (skype-skype is supposed to be free calling).
But if you want to do free calling, that is also possible (not with Skype though). See, /t5/Xseries/Nokia-X3-02-Fring-Skype/td-p/765625