I've searched the help topics but can't seem to find any information on whether or not the program is capable of it. This would help me tremendously by saving me the time it take to enter it into a calculator repeatedly and run the risk introducing multiple errors into my final answer.
I'm not sure what you mean by "integrating functions." Do you mean creating user-defined functions? If so then yes, it is possible using Visual Basic. Here's a good source for Excel questions: http://www.mrexcel.com/board/index.php
Integration is no more than a sum - implement the function with the results for each interval, and sum them up should give you the result. As noted above, you can always use VBA to code the function.
Perhaps these links will be of some use. They all contain downloadable examples: Applied Calculus Numerical Integration and Differentiation (includes Excel examples) Excel Skills for Calculus
What sort of function are you integrating? It might be simpler and more accurate to integrate if analytically, and then numerically evaluate the result in Excel or whatever. Another option is to use symbolic math program, like Mathcad or Mathematica.
