To be honest, its really not worth the trouble keeping your computer online 24x7, and chances are you are not allowed to even run servers on a retail line, regardless of the isp.
It would be worth it to just save up, and by a prepaid plan from a good web hosting provider that will take care of all the server side stuff, then you can just focus on your web site and not keeping your home "Server" up .
- Eddy