How to transfer documents from my toshiba laptop to my iphone 3gs?

Okay, so I have some documents like reports, and important files that I want to transfer from my computer to my iphone 3gs…
How do I do it? I have a USB iphone cable… But do I need to have itunes?
I tried plugging in the phone to the computer and i tried dragging files to the phone, but it didn't let me transfer over the files…
Please someone tell me step by step what to do?

There's a couple of options you could use.

1. Get a copy of FileZilla server and an FTP app for your phone. Run the server on your laptop and use FTP to transfer the files to your phone.

2. Use a cloud server like dropbox where you can get 2G of free file space and access them from wherever you need to.

I think you can try some program to help you. Well, i can suggest you to use AnyMP4 iPhone Transfer. With it, you can transfer files between iPhone and computer without any loss. Also, you can transfer multiple files at the same time. It will save you a lot of your time.