If you have Paintshop Pro, look for a good tubing tutorial for your software version.
It will show you how to isolate an object in an image and remove the rest of the image, leaving just that object with a transparent background. (you could skip the part where you make the actual .tub file from it, and save it as a .psp or .png instead, and then use it as you wish)
Since I wouldn't know what version of PSP you have (or if you have it at all), I can't really recommend a tutorial for doing it. It's slightly different in each version. Older versions don't have all the same tools that a newer version of the software has, and hence, the process used to get the best results is different.