Thanks DVDdoug,
First, to alleviate your concern, I have both 12V and 5V relays, and I have not connected a 5V relay to a 12V source (and I don't plan on doing so). Here's an example schematic that is basically what I did for the first relay: http://i.stack.imgur.com/VcJCl.gif. For the others, I simply moved (and flipped) the transistor to the other side of the relay so that it is switching the voltage going into the relay instead of switching the voltage coming out. This is the only change I made, and this has resulted in a voltage of ~4.5V going into the relay coil instead of 12V like the first relay circuit is doing. This seems really strange to me that it is behaving this way, but after a bit of research it is apparently normal. I just want to make sure that this won't damage my digital pins. It sounds like I won't since I have the 1K current limiting resistor on the pins... But then am I basically activating the relay using the current directly from the pin, or is it using the current from the 12V source but limiting the voltage?
Thanks,
Chris