How to hook my dslr camera up to my computer to show pictures?

I'm doing a photoshoot in a couple weeks and I really want to hook my Nikon D3100 camera up to my macbook pro, so I can see the pictures right after I shoot them is there a program I can download?

No matter what you do, you are going to have to use either the USB link or put the SD card in the computer. Your camera has no wireless link so you're stuck with physical connection.

The regular software that comes with the camera should be adequate to transfer and display the photos and, since they are designed to work with that camera, they are going to be the fastest and most accurate.

Not all cameras support tethering, nor do all programs support all cameras for it.

You will need to read your cameras manual (and possibly call Nikon 1-800-NIKON-UX 1-800-645-6689 to ask) and the software you use to see if that camera can be "tethered".

You could consider using an eye-fi memory card with built-in Wi-Fi in your D3100.

Eyefi claims their sd cards support the D3100 i(see links below), but unless you have access to a Wi-Fi-network nearby, you'll have to set up a so-called ad hoc Wi-Fi connection between the sd card and your macbook, which can be a something of a headache and may need additional software.