Need help with making a voting plugin/widget

I’m looking to make a voting widget/plugin. I want visitors to my website to have the ability to vote for links. I want a box where people paste links that they found interesting and then they hit the submit button. I want a counter to count how many times that link has been submitted and the ones with the most will rise to the top of the list. I want to have the list appear in my wordpress sidebar. I also need something to stop the same IP from posting the same link over and over again. Can someone tell me what I need to get this plugin working? I’ve never made a widget/plugin before so any help on getting started would be great.