New to programming need help

I am new to programming web services and websites but am a little familiar with VB. I am trying to figure out what would be the best way to go about creating a program to perform the following task. I am trying to control how much time a person can spend accessing the internet. I have kids that are allowed to access the internet for 1 hour a day. So I am trying to create a webpage/webservice that will track how long they access the internet and block them after there time is up. The program or webservice will need to know the time they login and then once the allowed time elapse run a script that will block the users IP address in our firewall. I already have the script to block IP address I just need the App/web service to handle the access portion.

I figured they would have a page that they log into, once they successfully login it will log the time and then start counting down the minutes. If they stop before the hour, it will need to log the remaining minutes for that day. Minutes would be accumlative so if they kid did not use the entire hour that day whatever was remaning could be used the next day. Once the time expired they would receive the notification and a script would run to block the IP address.

I figured this would be a good way for me to learn more about web services or web app program. Any guidance and assistance with this would be appreciated.

Thanks