Is there a software/interface that will allow me use my laptop trackpad for drawing/sketching? Or what would be a good device that I could use to do the same?
The touchpad can be used this way, but it's not really designed for it. A good trackpad for drawing will not only pick up motion, but coordinates, and touchpads don't do this.
However, you can buy drawing tablets. They basically operate similar to the touchpad, but are larger, do take into account coordinates, and are designed just for this purpose. Wacom is the most popular manufacturer of these devices, though you can probably find others as well.