This is probably a stupid question, but I was wondering how do you get those screenshots of the skin like they have on some webapages?

One way u can try
 

this is how u can capture the screenshot...on your keyboard...press the printscreen button to print the screenshot u want...then open a photo editing program like Adobe photoshop or some others...then paste it into the program...that's it...no need to purchase some special programs that do specifically capturing screenshot...hope this help...Peace Out