What Software do I need for this?

There are a number of companies out there providing this type of software. Some of them provide it to you via their website, while others allow you to download the software to your computer. I'm sure you probably want this for free too, so your 2 best download options are Google Earth from Google, and World Wind from Nasa. If you'd rather use an online program, then Microsoft Terraserver, MSN Virtual Earth and Google Maps are the way to go.