Depending on exactly where you live there may be city, county, state, or national laws that specifically prohibit what you have been doing, and intend on continuing. If there is no specific law rgarding it then it is usually placed in the general categories of "theft of service" and/or "unauthorized access of a computer network." In addition, the forum policies specifically prohibit asking for assistance in gaining unauthorized access to a computer network. Thus, I must not lock this thread.
My suggestion: Stop what you are doing immediately. Regardless of whether or not you get caught (and you would if they ever check their access logs) and whether or not it is specifically prohibited by law in your area it is most definitely unethical.
Can a wireless router allow me to connect to the internet through another wireless signal? I live across from a school with wireless internet, and until a few days ago (when my adapter broke) I was leeching their connection. Since I now have to buy a new adapter, I noticed that a router costs the same as the adapter, and I was wondering if I could use the router to connect to THEIR wireless internet.