In short, no.
Webcams/digital camera's are 'devices' usually on USB, but some may work on firewire. The USB interface requires a 'host' to communicate with a device, or many devices on the bus. The same goes for a wifi dongle. So you would need at the very least a host interface between the two. And THEN you have to think about the software side, since a 'wifi dongle' will just transmit/recieve data given to it from the host - any wireless network it connects to would ahve to know what that data actually means.
Probably the easiest/most conveneient way would be with a small PC. Smallest, but more time consuming (even if you already know C coding and the USB protocol insideout) would be a microcontroller with 'on-the-go' USB. That is a USB device inside the microcontroller, which has limited capability to perform as a host.
Would be nice to make a wireless camera/webcam, but I'm not sure theres much of a market for a relatively cheap 'wifi cam'. I'm sure there are wifi cameras around, but wifi/bluetooth has limited range, so I'm guessing any available devices would be pretty expensive. Saying that, china seems to come up with all manner of consumer goods - not the most reliable, or the best quality, but certainly cheap and dandy.
**broken link removed** ?