IPhone 4 video chat questions.

Ok so im looking to get an Iphone 4 through verizon, im not using my upgrade.. i have an Fascinate my friend wants my phone, she is able to upgrade. So i asked if she could just get an Iphone 4 for me an i would then switch phones with her. How ever i have a few questions. Can i DL Skype app on the iphone and Skype with people using a computer seeing as it has a front facing cam. Also i kno iphone has facetime but what if i want to video with someone that has the Evo 4g. Can i do that?