Go to the last cell in a column that contains a value

I have searched many forums but am having trouble finding and example of exactly want I am trying to achieve.

In the cells in column A I have a formula that if the corresponding cell in column B is populated then insert a value into Column A.

I am trying to source a piece of code that will find the last cell in a column A that contains a value and then turn the calculation into a value with edit copy and paste special values.

Can anybody help me.

Thank you.