Read USB data

Hello,

What Software-tools can I use to read data I/O on an USB port?

Thanks in advance!

Can you be more specific? What is the goal of your project?

Try googling for it, you get links like this:- http://www.lvr.com/development_tools.htm

However there is nothing you can do with the arduino without extra hardware as you never get exposed to the USB data lines.

Are you trying to debug / sniff USB data on a gadget connected to a PC?

I've used a program called SnoopyPro for this (under Windows at least) - looks like here may be its current official home. Can't really be of much without knowing more about what you want to do.