Gas Tank Farting? Help!

Hey SVX'ers! Wondering why the gas tank (at least I thinks that's where it's coming from) makes a gargle (bubbly sound) when I'm about to start the car when its only warm or hot. Again, as mentioned, it only happens when the car is either hot or warm. Sometimes I just have to turn the ignition without starting the car and I begin to hear garrgling sound which eventually subsides after a few seconds. I've also noticed that the gas cap leaks a lot of air when removed when warm at the gas station. Could they be related is that normal? It it the gas cap? Trust me it's not from the previous meal that I just ate! Any ideas? Post away!