What many people do is buy an "IP Camera" that connects directly to your home network (either wired or wireless) to send images to wunderground.
However, wunderground webcam support isn't very stable at the moment. My webcams still come and go depending on wunderground's mood.
Wunderground planned to eliminate webcams last year as they felt they could no longer support them due to age of the code and cost of maintenance. There was a huge outcry from users, so they did an about-face and decided to continue webcam support.
However, they said they need to re-write their code and they expect that to take several months at least.