Ami,
There are countless inexpensive wireless webcams available. I'd go down that route.
Otherwise, you need only get a wireless USB adapter, which there are many.
I'd say build your own, but the prices can't be beat.
Cabe
cabe i don't mean what you said . the web cam 'll be in the entrance of a building and the computer 'll be in the control room . now the question is how to connect between them wireless by using wifi not by using usb cable.is it clear?
cabe i don't mean what you said . the web cam 'll be in the entrance of a building and the computer 'll be in the control room . now the question is how to connect between them wireless by using wifi not by using usb cable.is it clear?
Yes, the are plenty of wireless wifi webcams. See amazon.com for example.
Cabe
did you mean an ip cam? i don't want to use an ip cam because it is expensive and i want t take the advantage of cheap price of the traditional web cam to optimize between quality and cost.