No, you cannot control an iPod Touch through the internet. However, the iPod Touch does have the ability to go onto the internet, if that is what you are asking. You can do a remote-wipe if you sign up for a Mobile Me account and the iPod is a 4th generation iPod Touch, but that is the best you can do.
What do you need to use WiFi on your ipod touch i have a broadband modem conected to internet but not wireless internet and my ipod touch 3g 32gb?
Wi-Fi is Wireless Fidelity, which is wireless internet. If you do not have Wi-Fi (wireless internet), you cannot access the internet from your iPod Touch. You will need a Wi-Fi router that will connect to your modem and your computer, which will allow your iPod Touch to access the internet through Wi-Fi.
You don't "buy" internet for your iPod Touch. The iPod Touch comes with a built in Wi-Fi receiver, so you only need to be near a wireless router to have access to the internet. This is exactly the same network that you get on with your laptop (and possibly your phone), so if you have a router, you can go on the internet.