Bluetooth is a short-range wireless protocol used to connect two devices (or a device and a peripheral or accessory) within close proximity. You'd use Bluetooth to send files from your phone or your friend's while you were in the same room, or from your computer to your phone while sitting at your desk (if your computer has a Bluetooth card, which many laptops do), or to connect your phone and a Bluetooth earbud. Bluetooth isn't the same thing as wireless internet (called 802.11 or "WiFi") at all. You can't connect to the internet using Bluetooth, so there's no such thing as a "bluetooth website", except perhaps a website that has information about Bluetooth.
If your phone has a 3G internet connection through your mobile provider, you can access most websites normally and upload files from your phone that way. Otherwise, you'd have to connect your phone to a computer, either by a cable or by Bluetooth (again, if the computer has Bluetooth), transfer the files to the computer, and then upload them to the website.
