You can make video call, but the user of other side will not be able to see you as Nokia Lumia 710 doesn't has front camera. May be you will get a place to change the camera settings to make the rear camera as your primary video calling camera. However you can try these 3 software to accomplish video calling:
Skype - http://www.windowsphone.com/en-gb/store/app/skype/c3f8e570-68b3-4d6a-bdbb-c0a3f4360a51
Viber - http://www.windowsphone.com/en-gb/store/app/viber-messenger/f4631757-d1f6-4727-bd65-e6bc6c8e35da
Tango - http://www.windowsphone.com/en-us/store/app/tango-video-calls/fe30c379-d111-427d-894f-dc3bfa0ec371
Although Skype is the number one software to make video calls on Smartphones and Computers, it seems the software doesn't has complete error free support for Windows Phones as of now. Many users are reporting problems in windows phone support community. Hence, I wouldn't strongly recommend it for you.
This will work on your device without any problem but not so high quality. I would recommend you to go for the third one:
Yes, they (Tango community) know how to keep their application updated by solving errors, bug fixes etc. You can make video calls using this application. I recommend you to go for this app in windows phone market (The link given above).