I was just wondering what the equation is to find the 555's output frequency is, when a control voltage is applied to pin 5. That would be very useful for me to know!

[Edit By OP]

So based on what Spehro Pefhany said, the equation for the output frequency (Substituting the equations for the high and low times) would be:

Where:

\$V_{Control}\$ is the control voltage

\$C \$ is the timing cap

\$V_{cc}\$ is the supply voltage

\$R_{1}\$ and \$R_{2}\$ are the timing resistors