I own one of those little pinhole 'spy cameras' that connect to your tv.and are powered by 5v? With an arduino and ethernet shield, would there be a way for me to create an IP camera type thing?
No. Assuming your camera has an analog video output, you need a way to sample, digitize, encode/compress and transmit it over the ethernet. All of these are far beyond the capabilities of Arduino.
You could do that with a raspberry pi and a USB video capture card, perhaps (you would need a capture card with good enough linux support to work on ARM). An arduino does not have anywhere near the required horsepower.